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Volume 1 |
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Ventsim Visual™
User Guide
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Volume 1 |
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Ventsim Visual™
User Guide
Ventsim Software
Ventsim
Visual™ User Guide
Version 0.95
The author and the supplier has no liability to the licensee or any other person or entity for any damage or loss, including special, incidental or consequential damages caused by this product directly or indirectly.
The software is supplied "as is" without warranty of any kind, either expressed or implied. Warranties of merchantability or of fitness for any purpose are specifically disclaimed.
ã Ventsim Software
Chasm Consulting
PO Box 2006
Aitkenvale Qld 4814
admin@ventsim.com
This manual presents a guide to the effective use of Ventsim Visual™ ventilation software for mine ventilation simulation and design. It does not profess to be a ventilation engineering guide and as such should not be used as a substitute for existing ventilation texts for underground ventilation and environmental engineering.
The manual may contain simplifications and does not attempt to explain many of the complex concepts and methods used in environmental engineering. It is highly recommended that users of Ventsim Visual™ have at least a basic understanding of ventilation and simulation concepts in order to correctly input and interpret the program functions and results. Many excellent texts and papers exist for mine ventilation, not the least which is the late Malcolm J McPherson’s ‘Subsurface Ventilation and Environmental Engineering’, from which Ventsim Visual™ draws much as the methodology for thermodynamic simulation.
CHAPTER 1 – Ventsim Visual™ – An Introduction
CHAPTER 2 – Ventsim 3.9 to Visual Guide
Drawing in the Third Dimension
File Input and Output Functions
Chapter 10 - Building a Network
Chapter 11 – Considerations for Thermodynamic Simulation
CHAPTER 1 – Ventsim Visual™ – An Introduction
CHAPTER 2 – Ventsim 3.9 to Visual Guide
Drawing in the Third Dimension
Page Setup / Print / Print Preview
Diesel particulates [ADVANCED]
Financial Simulation [ADVANCED]
Simulation Environments [ADVANCED]
Examples of Rock Characteristics
File Input and Output Functions
Recirculation Simulation [ADVANCED]
Financial Simulation [ADVANCED]
Chapter 10 - Building a Network
Chapter 11 – Considerations for Thermodynamic Simulation
What portion of the air is cooled?
Wet Material / Dam / Flooded airways
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Chapter 1 |
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Ventsim Visual™ is a technical successor to Ventsim 3.9 which was first developed and released in 1993, and was widely lauded for its simple interface and 3D wireframe approach to displaying ventilation networks. |
The relatively recent introduction of affordable 3D graphics hardware into everyday PC’s encouraged a new approach with Ventsim ventilation software.
It became clear soon after the introduction of Ventsim that very sophisticated and complex networks were being developed with the program, however the application and analysing of these networks was restricted by the shear amount of data being manipulated. In addition, in networks of many thousands of airway branches, serious mistakes could often be made in the entry of data without being noticed. Viewing and editing of large datasets was becoming increasingly problematic, and use of these networks by others not familiar with the network was becoming more difficult.
In general, the observation was that many sophisticated ventilation networks were being developed by bright engineers, but then simply gathered dust once these engineers moved on, and new engineers abandoned trying to decipher them.
Another key factor to the development of the next generation of Ventsim was the increasing demand to simulate and design underground environmental conditions, suitable for mine workers and equipment.
As a result, Ventsim Visual™ Standard and Advanced were developed to address these requirements. Primarily, it has been designed as a ventilation tool, which can operated independently of other mine planning packages, but maintains a level a compatibility which ensures data from mine planning packages and other ventilation software can be passed to the program.
Ventsim Visual™ provides a full toolbox of tightly integrated utilities to analyse ventilation flows, heat, contaminants and financial aspects of mine ventilation. Building on the success and experience of fifteen years of Ventsim implementation at over 400 sites, Ventsim Visual™ goes a generation further in its approach to ventilation simulation and analysis, and sets a new standard in ventilation software design and implementation.
Ventilation has been a primary concern in underground mines for hundreds of years, but until the introduction of computerized network analysis in the last 40 years, the planning and modelling of ventilation was largely a black art, relying on experience, guesswork and extensive calculations.
Even when computer ventilation software allowed simulations of large networks of underground airways, the process of entering and interpreting results still remained a job for experts in the field. Ventsim Visual™ aims to make ventilation simulation and design accessible to any mine engineer or ventilation officer, even those without substantial ventilation experience.
Ventsim Visual™ Standard provides the user with the tools to;
• Simulate and provide a record of flows in an existing mine.
• Perform 'what if' simulations for planned new development.
• Help in short term and long term planning of ventilation requirements.
• Assist in selection of types of circuit fans for mine ventilation.
• Assist in financial analysis of ventilation options.
• Simulate paths and concentrations of smoke, dust, or gas for planning or emergency situations
Ventsim Visual™ Advanced provides additional tools to;
• Undertake full thermodynamic analysis of heat and refrigeration in underground mines.
• Take into account air compressibility for deeper mines.
• Provide tools for analysing multiple different airways size options, both financially and for establishing ventilation capacity.
• Provide a tool to check for recirculation in mines.
• Simulate Diesel Particulate Matter (DPM) concentrations through a mine.
Ventsim Visual™ has been written to make the process of ventilation network analysis as easy to use as possible. Both versions utilise sophisticated 3D graphics, driven by a fully graphical mouse driven interface. Ventsim Visual™ is compatible with Microsoft Windows XP or VISTA. The software can also be run on Apple Mac Computers with suitable graphics hardware, running Windows under dual boot emulation.
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Chapter 2 |
Ventsim Visual™’ is a substantially different program than Ventsim 3.9 and takes a new approach to ventilation display and simulation. This section will give you a brief overview of the major changes if you are familiar with Ventsim 3.9, and may also assist if you are familiar with other ventilation software packages.
Ventsim Visual™ uses a 3D perspective view. |
The three dimensional (3D) perspective view is rarely used in CAD or Mine Planning packages, except occasionally for final presentation purposes. The perspective view tends to distort distances and true directions and is therefore largely unsuitable for detailed engineering drawing. An orthogonal non-perspective view however is not required for ventilation modelling, which relies more on effective data presentation.
The Ventsim Visual™ ApproachTo create a user friendly, graphically rich program and interface, which shows the maximum amount of relevant data, in the most efficient and understandable way. |
A 3D perspective view is the way we look at the world and when used to view computer models, it is natural and easily understood, particularly to someone unfamiliar with your network.
Airway solids shown with true dimensions and shapes allow quick appraisal to check whether dimensions are as intended. The author has found numerous examples of Ventsim 3 networks loaded in Ventsim Visual™ that immediately show inadvertent incorrectly sized or shaped airways which may prevent the network from simulating or balancing as expected.
A perspective view also permits closer visualisation of specific parts of a network, while other parts are hidden or obscured by distance. In cluttered large networks this can help clarify intended data significantly.
They say a picture is worth a thousand words. Animation may therefore be worth a thousand pictures. Ventsim Visual™ animation again demonstrates a key feature of the software’s presentation of complex data. By animating flow arrows, fans and heating/cooling sources, Ventsim Visual™ can show a huge amount of data in a way that the human brain can quickly visualise and interpret. Animated flows show the direction and relative speed of all airflows in a mine over potentially thousands of airways. Animated fans show whether they are turned on or off, while dynamic colouring draws the user’s attention to specific data ranges. Using only animation and colouring of data, Ventsim Visual™ users can process and analyse complex networks, without having to interpret a single line of textual data. In addition, it makes presentation of data very effective to the layperson (who often control budgets and have to make decisions regarding investing in costly ventilation infrastructure)
There no longer needs to be a surface level elevation. Any airway can be connected to the surface at any place in the mine, by clicking on Connect to Surface in the airway Edit Box. Ventsim Visual™ will calculate which end is connected to the surface, based on simulated airflows in the mine.
A level database, although still useful, is no longer mandatory for viewing different elevations of a network. While an overarching single elevation level covering all elevation ranges is still recommended, any elevation range can be viewed at any time by Right Clicking the screen, choosing Select Level from the context menu, and then clicking or fencing the area you wish to view. Once selected, Right Click to view the results. In addition the select level function can be used to quickly limit an elevation range, or multiple ranges.
Airways no longer need to be connected to another and can be left open ended, as would be the case in blind development headings. Because this may still cause unintentional problems (such as airways not joined as the user intends), Ventsim Visual™ will alert the user to these during simulation. These warnings can be turned OFF in the settings menu, or disabled individually by clicking Allow Open End in the edit box. No airflow will travel through open ended airways, unless connected to surface.
“No Entry / No Exit” errors are largely abolished with Ventsim Visual™. Providing the airways are connected to a part of a network where a pressure can be derived, Ventsim Visual™ will automatically reverse and adjust airways into a node.
Finally, airways drawn by the user that cross other airways, will automatically have a junction node inserted, joining both airways.
The single biggest change to Ventsim Visual™ is the management of data types. Around seventy (70) different data types exist in the Advanced version, all of which may be displayed as text on the screen, in a spreadsheet or as a colour range.
This creates a rich, but potentially confusing interface. To simplify things, Ventsim Visual™ uses both a Colour Legend control and a Data Selection control form to assist in rapid analysing and changing of on screen data. These two controls can be utilised via the view menu, or from the toolbar.
It is important to note that the Colour Legend control can display data independently of the text data which is shown on screen (for example pressures can be showed at a colour range, while text data could show air flows. Colour ranges can be adjusted in the Colour Legend control with the slider bars, or by manually entering new ranges.
Ventsim has switched to a more conventional Eastern / Northing / Elevation coordinate approach. The relative directions on screen of these coordinates can be changed in the Settings menu.
Ventsim Visual™ allows decimal point coordinates to be used allowing more accurate placement of airways. While this will have little effect on ventilation flows, it removes the ‘saw tooth’ effect often seen in the Ventsim 3 integer coordinate display
The Edit Box now acts as a powerful editing and information tool for airways in a network. The Edit Box may be left open permanently, and will update with information from the airway clicked on during viewing, editing and adding modes.
To view airway information for example, leave the Edit Box selected on the Information Tab, and airways throughout a network can be quickly analysed by clicking on the airway. Likewise, the Fan Tab could be left open, and operating fan curves can be analysed quickly at different point in the network in the same way.
To modify data in an airway, simply click on the cell you wish to modify and change the data. The airway will automatically update when Apply or OK is pressed, or when another airway is selected. Multiple airways can be selected for simultaneous editing by fencing or selecting the airways while in Edit Mode, and then clicking on any selected airway. Any data within the Edit Box changed during editing multiple airways will be changed for all the selected airways. For example, if all selected airways require a width of 6m, then after changing and applying the Width in the Edit Box, the width (and only the width) of the selected airways would change. All other attributes (even if different between the selected airways) remain unchanged. Data that will be changed turns blue after modification. To abandon these changes, select Cancel from the Edit Box before moving to another airway.
Finally, by all means experiment with the program. Load up and view some of the included demos. Most features have a Tool Tip attached to them, which will provide further information if the mouse cursor is hovered near them. Ensure you save your network files frequently and create backups where necessary.
Good Luck
Craig Stewart
Author Ventsim Visual™
Ventsim Visual™ operates in a full three dimensional (3D) perspective driven environment.
Ventsim Visual™ View Window
The success on how to utilise some of the unique aspects of a 3D perspective view comes from an understanding of how it works. Ventsim Visual™ has a number of guides to assist in viewing and construction in 3D.
The view is essentially a view seen from a ‘camera’ floating in space, aimed at a point of focus. Your eye is the camera. The point of focus is always in the centre of the screen, at a pre-determined distance away from the camera.
You can move closer or further away with the Mouse Scroll button, and rotate around this point of focus with the Mouse Right button, but you cannot move the camera past the point of focus, or to the left or right, unless you move the point of focus.
There are several ways to move the point of focus;
1. Draw a window with the mouse around the area you wish to focus on. The focus will move to the centre of the window, at the closest distance of an object or airway in the window.
2. Drag (pan) the screen with the Centre mouse button. The point of focus will move along the current horizontal plane with the mouse cursor
3. Click on an airway, with the Mouse Middle button (or a Right/Left combination for those without a 3 button mouse). This will automatically put the focus onto the clicked airway at the same viewing distance as was previously set. If the object being clicked is a long way away, this has the effect of quickly flying through space towards that object in order to maintain the same view distance as the previous point of focus.
The Elevation of the point of focus can also be changed by selecting the Shift key while using the Mouse Scroll button. A transparent grid (if the grid is turned on) will show the horizontal plane of the point of focus.
![MCj03969060000[1]](Manual_files/image007.gif)
The Edit Plane is a horizontal plane at a set elevation. By default, any new airways are initially constructed on the edit plane. The edit plane can be viewed by ensuring the grid function is turned on. The plane will be crossed with grid coordinate lines. If Shift is selected the edit plane will be made semi-transparent which will indicate where it intersects existing airways.
Figure – The Edit Plane, shown with the SHIFT key pressed
To move an edit plane, select a new point of focus, or use the Shift-Mouse-Scroll function described above. The coordinates in the status bar at the Bottom Left corner will always show the elevation of the edit plane.
Hint : The Edit Plane will also temporarily move automatically to the level of an airway being drawn from another airway. Additionally, the edit plane and point of focus can be moved manually by the Set Edit Plane function in the menu bar.
Figure : True Vertical Line showing an airway drawn vertically above (and intersecting)
another airway
Figure: True Vertical Guide Line helps guide a connected shaft to vertically join into
the airway below
Drawing in three dimensions can be a challenge when a view is being displayed on a two dimensional monitor. Ventsim Visual attempts to alleviate this problem by only drawing on the horizontal plane except when the shift key or right mouse button is pressed.
3D perspective views do not necessarily show a vertical object as pointing straight up. As objects move further left and right of the point of focus, they ‘lean’ over away from the centre of the view. To assist the user as to which direction is truly up while creating or editing airways, a true vertical line is displayed while drawing, moving or copying. If the object being drawn aligns with the true vertical line, then it is vertical. The true vertical line can also assist in locating airways directly under or over other airways at different elevations by observing where the line ‘intersects’ airways above and below the current point being edited.
To simplify construction of airways, initially all drawing, moving and copying of airways defaults to the horizontal Edit Plane, regardless of the orientation of the view screen. To assist the user further, airways being drawn or moved will automatically ‘click’ and join to airways under the mouse cursor, even if at different elevations or distances away.
If airways are drawn in isolation (not connected to other airways), they will use the default airway settings specified in the Settings form. If airways are drawn connected from another airway, they will inherit the settings from the airway from which they are drawn. Airways can be drawn from another airway end (node) or from any other point along an airway. Ventsim Visual™ will create a new node (or junction) if none already exists.
Hint: Ventsim Visual™ can detect whether an airway being constructed crosses the paths of other airways. For example, if a long airway is drawn from one point to another, over which it crosses the paths of existing airways, Ventsim Visual™ will join this airway into the crossed airways with new nodes. This will only happen in the drawing mode. If airways are imported (from a DXF for example), crossed airway junctions will not automatically be detected).
To draw in the third dimension (up or down in elevation) where there is not an airway above or below to click to, first draw the airway to the desired horizontal (plan) location, then press the Shift key. The Edit Plane will turn semi-transparent, and further movements of the mouse will occur in a Vertical plane parallel to the computer screen. The Edit Plane will follow the vertical movement, assisting in showing where the cursor is in relation to other airway elevations. In addition, the numbers in the lower left status bar will show the elevation and coordinates of the point.
Picture showing inclined airway being drawn down to the elevation of the level below
Airways can be manually added, moved or copied by selected a manual coordinate entry system. To activate this system while in draw mode, select the ADD button from the toolbar, and choose one of the sub-options from the button. To activate this system, when moving or copying, simply click an existing airway while in the Move or Copy mode. A coordinate window will show and the coordinates (or offsets) of the airway can be entered.
Coordinate entry system
Airways can be copied, much in the same way as the Move function. An airway can be ‘grabbed’ with the mouse and ‘dropped’ in a new location, or the airway can be clicked and manually copied with new coordinates. In addition, a group of airways can be selected with the Select button, or by drawing a fence around the airways, and then clicking or dragging one of the selected airways.
Example of copying a selected group of airways
Depending on where the airway is clicked with the mouse in Move mode, either end, or the entire airway may be moved. If the ends (nodes) of the airway are connected to other airways, they will be stretched to accommodate. An airway can be ‘broken’ away from a node by selecting it a small distance back from the node, and ‘dragging’ it away with the mouse.
Multiple airways can be copied or moved by Selecting the airways (with the Select button, or by drawing a Fence around the airways while in Move or Copy mode), and then dragging the selected airways with the mouse, or clicking one of the airways to manually enter coordinates.
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Examples of Moving Airways Upper left : Selected airways are moved simultaneously Upper right : Airway junction is moved with all attached airways Lower left : Airway is ‘broken” away from node and pulled away with mouse Lower right : Airway junction is moved vertical by pressing shift while using mouse. |
ORIGINAL
Status Bar 3D Viewer Menu Bar Tool Bar
Main view window
The main Ventsim Visual™ window contains all the functions you will require to create, edit, view and simulate airway networks. Note that some of these functions may differ between Advanced and Standard versions.
Status Bar
Erases the network currently in memory.
An option is given to save any unsaved changes from the current network. The previously used Level, Layer and Fan Database will be retained for the new network.
Loads a pre-saved network.
You can also open Ventsim Visual™ files by dragging file icons from your Windows folders onto the Ventsim Visual™ screen.
Joins two networks together instead of erasing the currently loaded network.
Similar to the Open command, this may be useful for joining separate networked areas of the same mine. Caution should be taken however, as duplicate branches are not immediately checked when the networks are merged (duplicate branches will be subsequently be deleted if an attempt is made to simulate the network).
Adopts some of the attributes of another network.
Ventsim Visual™ files contain many different components for the network, such as fan databases, file and simulation settings, level and layer database and many other options. Instead of setting up new parameters for you network, these component can be loaded from an existing file without deleting the airway data in the current file.
Once a suitable file is selected, an option panel is displayed to allow the user to select various components they wish to inherit from the saved file. Once loaded, these components will become part of the existing file.
CAUTION – Some components such as fan databases and mine levels may not correctly map to the existing network’s fans and levels, particularly if (for example) fans within the database are in a different order. These may need to be manually corrected by checking and re-editing fan airways to ensure the correct fans have been placed.
The start up settings for Ventsim Visual.
The defaults file is stored in the user’s personal Windows directory. The file is loaded when Ventsim Visual™ starts and specifies the settings, behaviour and fans when the program is first loaded. Each user who logs on to the computer will have a different default file which is initially created when the program is installed.
Ventsim Visual™ files have a copy of defaults stored within the file which may have been modified after the network file was started. This will override the standard start up defaults when the file is loaded.
Reloads the original defaults file that is first loaded when Ventsim is initiated.
This may be required if the default settings that are automatically loaded with a Ventsim simulation file are incorrect or out of date, or you wish to overwrite the current file settings.
CAUTION – This will reset all file parameters such as fan databases and graphics options. If you wish to only update selected components, use the inherit function to load selected components from an existing file.
Saves the settings currently loaded in memory to the defaults file.
These will be loaded automatically next time the program is run.
Restores the defaults file to the original file created when the Ventsim Visual™ program was installed.
Saves changes made to the network.
If the Ventsim title bar shows that the network is untitled, the user will be prompted to select a name before the file can be saved.
Saves the network, but gives the option of saving under a different name.
Ventsim can be saved in one of two formats. The default format in the VSM file which is the standard file format. This format is highly compressed and cannot be read by other programs.
Ventsim Visual™ files can also be saved as a Text format. This format follows the standard TAB separate values format and can be loaded by programs such as Microsoft EXCEL, WORD or ACCESS. The internal contents of the file can be viewed, modified and resaved as a Text file. The Text file can be reloaded into Ventsim Visual™ providing the basic structure and the HEADER and FOOTER tabs remain the same.
Templates are collections of file setting
components that you may want to either start a network with, or apply to a new
network. Much like the ‘inherit’ function, templates can be constructed from
selectable components currently loaded in Ventsim Visual™ and saved for later
use. Templates will not overwrite currently loaded airway data, but will
simply update the settings components belonging to the data.
Save the template in an accessible file location. A descriptor can be saved with the file to explain information about what components have been saved. To use the template in future, either double click or load the template directly in Ventsim Visual™. When loaded, the descriptor will display a window showing what components have been applied.
HINT : Templates support drag’n’drop. Simple grab the template file from a windows folder or directory and drop it on the Ventsim Visual™ screen. The current file and Ventsim Visual™ settings will be instantly updated.
CAUTION : Once again, as with Inherit and Defaults, some components saved in a template file such as fan databases and mine levels may not correctly map to the existing network file
Saves the current screen to a file location as an image file.
This file can be later loaded into documents or presentations from other software packages.
Import Data (TXT)
Imports network data from TXT format (text format with fields delimited by a TAB character).
This format is widely available through most spreadsheets and can be read into word processors. The standard format for a TXT file can be saved from Ventsim Visual™ under the SAVE AS command. Most of the components (such as fan database and colour settings) can be excluded from a TXT file, leaving only the main file component if desired. The main file component must have at least coordinate data for airways to load, as well as the header name for each column.
At a minimum, a TXT file must have a Header line (the first line in a Ventsim Visual™ saved TXT file), and a Completion line (the last line in a Ventsim Visual™ saved TXT file)
An example of a Ventsim Visual™ Text File Loaded into Microsoft Excel
Import Data (DXF)
Imports DXF formatted data (supported by most CAD and Mine Planning packages).
Note that only a skeleton network (with no additional attribute type data) will be created. The DXF file should contain only the network line strings that will form the network, as anything else will be ignored.
DXF files can be merged with an existing network (for example a mine addition), and then attributes (airway sizes etc) can be set within Ventsim Visual™.
HINT : Both TXT and DXF files support drag’n’drop. Simple grab the file from a windows folder or directory and drop it on the Ventsim Visual™ screen.
Allows the user to specify a unique file comment which appears in the top title bar.
This comment can help identify the date, name and purpose of the network.
Allows users to write an extensive descriptor regarding the function or description of the current network.
This is saved with the file for future reference.
Prints a graphic picture of the network in the View Window to an installed printer.
Only printers with Windows supported graphics capabilities will be capable of printing the network. As Ventsim Visual™ uses a perspective view, no particular scale is applied to the image. The image is sized to the maximum size of the page and orientation. To reduce colour output, the Ventsim screen colours can be changed under the Tools > Settings > Colours menu.
Quick loads files recently loaded or saved.
Loads a generic network of a mine.
This is for demonstration purposes only.
Opens the License Manager form.
Automatic License Activation and Release
Licenses |
Ventsim Visual™ licenses are floating licenses which can only be used on one computer at a time. They can be activated for use on one computer and then if required released and used on another computer (within the terms of the license agreement). License certificates are stored on the Ventsim server and prevent simultaneous installation of the same license on more than one computer.
As part of the digital licensing agreement, the license collects the computer name and user name of the computer that Ventsim Visual™ is currently activated on. This system protects against unauthorised use of the Ventsim Visual™ license and informs the user who has currently activated the software license.
Releasing a License |
Once a license is activated on a computer, it cannot be moved to another computer unless it is first released from the activated computer. If another computer tries to activate the same license simultaneously, this will be prevented and a warning will display the currently licensed computer and the login user name of the person who has installed it.
An internet connection is required to activate and release license certificates from a computer. If an internet connection is not available or an internet connection is not authorised by your firewall or company administrator, try to arrange a link to the http:\\ventsim.com website. If this cannot be done, a manual license transfer can be performed via email located under the file menu.
Manual License Activation |
In the event an internet connection cannot be made available to activate the software, and manual licensing system can be used. The manual licensing system still requires transfer of a file via email or FTP.
The license request file can be manually saved and emailed to license@ventsim.com. Once authorised (which may take up to 48 hours), an authorised license file will be emailed back and can be installed on the computer via the ‘LOAD’ option under the FILE menu.
This command closes Ventsim. Ventsim will prompt if your network file, fan database or defaults have not been saved since last modified.
Reverses the previous action
Undo is a fully functional undo facility that will undo a number of previous changes made to a network (up to the buffer size of the undo function). Note that while it will not directly undo a simulation, by pressing UNDO until your previously network is in place and then re-simulating, this will produce the same results.
Redo will reverse the result of the undo function.
Copies selected attributes from one airway to another.
Attributes are physical airway parameters such as size and friction factors. You can decide which attributes to copy from an existing airway by selecting the Select Manager form from the toolbar.
To copy attributes, select the Copy Attribute menu item, and click on and existing airway.
To paste attributes, select the Paste Attribute menu items and either click on an existing airway, OR fence a selection of airways, and click on any of the selections to apply the attributes to that group.
Copy airways from one Ventsim Visual™ program to another.
Copy and Paste Airways creates an exact replica of existing airways in a network and pastes them in the same location into the existing or new network. The function is primarily designed to copying and paste airways between network files. This may be required to update airways from a network that has been modified and added, into another network.
To use this function, ideally have two copies of Ventsim Visual™ open with different network files. Select the COPY AIRWAYS menu item, and click on or fence the airways you wish to copy.
To paste the airways, move to the new network (or load it up) and select the PASTE AIRWAYS menu item. The copied airways will be pasted into the new network.
If airways become duplicated in the process, Ventsim Visual™ will delete one of the duplicate copies.
Automatically locates specific airways and moves the screen to selected parts of a network.
Selecting one of the options will find and highlight the airway searched for. The option may be repeated for further branches by pressing the Find Next menu function, the Find tool bar button or by pressing <F3> on the keyboard. To find All instances of an airway (for example to find all airways with the name ‘shaft’ in the airway name, or to find all fans, click on an initial find type and then click on Find All. All items with these parameters will Highlight and Flash.
HINT – Pressing <F3> will rapidly allow you to search through a network, by repeatedly jumping to the next item. To view more detail about the items being jumped to, LEAVE THE EDIT BOX open. The EDIT BOX will instantly update with detail about every airway that is jumped to.
Fits all the display data into the view window.
CAUTION : If display data is from two regions a long way apart (for example data may have been imported into Ventsim Visual™ from a different coordinate system). The Fit All may not be able to accommodate the range of data attempted to be shown, or the camera may be too far away to view the data effectively. Ensure all data is in the same coordinate region before it is loaded or merged.
Sets the edit grid and point of focus to a specified coordinate or elevation.
New airways will be drawn on the specified elevation
Shows all elevations in the mine.
Levels are definitions or ranges of elevations on which airways data may be separately located and viewed. Elevation ranges can be given names (such as ‘1140 Level’) in the Level Database. Show All will force Ventsim Visual™ to show all elevations of airway data in your network, even if they are outside of the ranges specified in the Level Database.
Use the Right Mouse button and choose the context menu item Select Level to narrow your range to one or more elevation levels. Click on one or more airways or fence select a group of airways, and then Right Mouse click to confirm selection. All airways outside the elevation range will be hidden or made transparent. The level of transparency can be adjusted from the Colour Palette Manager.
HINT: Airways outside of the normal range of the LEVEL (elevation) database will be displayed as invisible or transparent. The LEVEL database should have a least one level which encompasses all elevations of airway data in your model.
Examples of the same area showing the effect of
‘Select All’ and ‘Select Level’
The
COLOUR DISPLAY MANAGER is a powerful tool which controls the colour
and transparency of all items on the screen.
Up to 50 types of different ventilation data can be automatically coloured and displayed in different ranges. The data type can be chosen by clicking the box at the base of the form, and selecting the data you wish to display. The colour display can work independently of the Text units displayed on the screen.
For example, if the pressure differences relatively to surface need to be viewed in different colours, select ‘Pressure – Relative P’. The colour range according to pressure will be automatically spread across airways, however can be manually adjusted by typing different range values in the top fields. Another option may be to view the Power – Ventilation Cost of airways for a year. The function makes analysing networks and viewing potential problems or solutions very quick
The sliders at the top left of the form can narrow the colour spectrum and range shown. By clicking the Check boxes below each slider, airways outside of this range can be made semi-transparent or even invisible by using the horizontal slider.
See the Colour Display Manager for further information.
Displays
the SELECTION DISPLAY MANAGER
The selection display manager allows fine details control over what is displayed on screen, such as graphics items, layers, levels and other options
The Select Manager allows control over graphics options, elevation levels, layers, saved views and copy and paste options
See Select Manager
Activates the flow animation system to animate flow direction arrows.
This function is for display purposes only, and does not play a part in simulation or control. Flows arrows are animated at either scale (real time) speeds, or by a factor of x5 or x10. Flow animation may be left on all the time, but will slightly hinder system performance, particularly on very large networks.
Controls
how much text in displayed on the screen.
Show ALL displays text for every airway, including short segments which may define bends. For complex networks, this can lead to a cluttered display, and is often unnecessary, particularly if the data shown is largely the same (for example airflows). For other items however (such a heat flows) this large amount of text data can still be useful
Hint : For data which may vary from one end of an airway to another (such as temperature), Ventsim Visual™ will always show the ENTRY data on the airway unless otherwise specified.
Show Limited only displays one piece of text for continuous airway segments with no junctions to other airways (for example a loop in a decline consisting of 10 airway segments, will only show one text data for all the segments. To force an airways segment to show data, use the EDIT box and click “Force Data Display”.
Saves the current view and stores the save name in menu for future recall. Save view will save all attributes in a view including RL levels, layers and display options. Saved views can be pulled back into any current window by selecting the saved name from the pull down view list.
Deletes the saved view stored in the CURRENT pull down menu list (and hence removes this name from the list).
Four view orientations are set as defaults
• PLAN
• EW SECTION
• NS SECTION
• ISO
These standard views will display the network at various orientations (although the network can still be orientated to the same orientations by using the RIGHT mouse button. These views cannot be deleted or changed
Caution: The Perspective view will distort some aspect of the views. For example, the plan view will show the airways at the EDIT grid level to plan, but airways above and below this elevation will appear larger and smaller respectively.
Any further saved views will be placed below these items. Saved views save the position, orientation, colour scheme and data types and attributes of the screen at the time at which they were saved.
Hint: Saved views are not only useful for recalling the location and orientation of a network. Because they recall selected levels, layers, data types and colours, they can be a quick way to establish a template to edit and view different data aspects of your network. For example, you may have an AIRFLOW view, custom set to highlight a certain range of airflows in different colours, while a ‘HEAT’ view may be saved to highlight a range of temperatures.
The RUN menu allows menu access to the main simulation functions of Ventsim Visual.
Standard Function
• Airflows
• Contaminants
Advanced Functions
Undertakes a thermodynamic simulation process, which derives initial airflow (and mass flows) from an airflow simulation. Thermodynamic simulation is complex and endeavours to simulate numerous parameters encountered in a mining environment. The simulation process follows well documented methods found in books such as “Subsurface Ventilation and Environmental Engineering” by Malcolm J. McPherson. Heat parameters that Ventsim Visual™ Advanced considers includes
• Heat and moisture derived from rock strata and ground water.
• Thermal properties of different rock types.
• Heat from point sources (such as electric motors), linear sources (such as conveyors), diesel engines and oxidisation of ores.
• Heat from auto-compression of air.
• Refrigeration and spot cooling of air.
• Changing densities throughout the mine, due to depth and temperature effects, as well as pressure from ventilation flows.
• Natural ventilation changes from changing densities.
• Artificial moisture from sources such as dust suppression sprays, spray chambers.
• Condensation from over saturated air
To accurately model a mine, all of these factors must be considered and entered into a network. If data for a parameter is not entered, Ventsim Visual™ will assume a default value specified in the Settings, and in most cases will simulate a result anyway. The accuracy of this result will largely depend on the accuracy of the entered data, and the default values used. More information regarding Thermodynamic simulation can be found later in the manual.
Simulates the spread of diesel particulates throughout a mine network, derived from diesel heat sources placed throughout the network. The simulation process assumes a steady state emission of diesel particulate sources and a uniform mixing process throughout the network and its junctions. Note that this may not always be the case in a real mine, where incomplete mixing and dynamic changing of exhaust emissions through the day, can change concentrations of diesel particulates at different times, however it provides a useful baseline to examine the effects of changing ventilation circuits and flow in a mine.
Examines a
network for paths which may recirculate airflow in a mine.
The definition of recirculation is the passage of airflow or a portion of airflow through the same point in a mine more than once. Ventsim Visual™ uses a custom algorithm to track the paths of every airflow throughout a mine, and report where airflow may recirculate. To prevent trivial reporting of recirculating air (such as minor leakage of air through a high resistance stopping) a tolerance of 1m3/s or 1% recirculation is used. Recirculating airflows are shown as ‘flashing airways’
Example showing a ventilation fan recirculating air
Assists in choosing the most economical airway sizes for the ventilation required.
This function can help optimise the size of shafts or horizontal development airways, to maximise cost savings in ventilation, while minimising mining costs. This function can only be used on a single airway (such as a shaft), or groups of airways with the same size (for example a decline system)
Optimum size
Increasing airway size is the easiest way to reduce friction pressure
losses and decrease ventilation costs in a mine. Increasing airway size
however creates additional mining costs, and this is further exacerbated by the
‘time value of money’ which dictates that a dollar saved in mining costs now is
worth more than a dollar saved in ventilation costs in the future. Another
factor to consider is how long the airway is required to carry air, which
affects how much ventilation cost can be saved in the future.
The financial simulator takes all this into account, and simulates up to 10 different airways sizes for an airway or group of airways, reporting the effect on mining cost and ventilation costs as an NPV (net present value) adjusted overall cost.
Example of a Financial Simulation Table
The system relies on the use of accurate mining costs to estimate the costs of different airway sizes and shapes. The correct power cost must also be placed in the Settings.
Input variables required |
Airway shapes: Round or Square. A set of 10 airway parameters is stored for each shape type. More complex shapes or fixed areas are not supported at this time.
Life: The life in years required for the airway to be in operation. This directly affects the ventilation operating costs of the airway, and the effect of time value of money.
Discount % : The time value discount of money per annum. The value of money will diminish over the life of project, meaning money saved up front (in most case mining costs) is worth more than money saved in the future (in most cases ventilation costs). Other names associated with factor include the discount rate, project hurdle rate, rate of return or NPV (net present value) discount rate. To use a value of money not diminished by time or to estimate undiscounted future savings, use a zero (0) rate. To evaluate projects however, most mining companies will use factors ranging from 5% to 15%, depending on the cost of money and the competing project values to be gained elsewhere with that money.
Sim : Check this box to include the airway size in the simulation. Airway sizes that are not reasonable or which do not deliver sufficient airflows should not be included for use as they can distort the graphs to excessive ranges.
Fixed Cost : Many airways, such a shafts have an initial setup cost to establish the mining method. This option is included to allow this to be factored in to the overall airway mining costs. It is applied only once for the airway, or group of airways selected, not applied to each individual airway. In most cases, horizontal development will not have a fixed cost applied against it.
Variable Cost :The cost per unit length of development or mining. Using this value, Ventsim Visual™ calculates total mining costs based on the length of the airways selected.
Financial Simulator Outputs |
Mining Cost Total cost of mining airways
Selected Annual Vent Cost Cost of ventilating selected airways for one year.
Selected Lifetime Cost Total cost of mining and ventilating selected airways for the life of the airways.
Network Annual Vent Cost Cost of ventilating whole of network for one year
Network Lifetime Cost Combined cost of mining selected airway plus cost of ventilating whole of network for life of the airways.
Sel Airflow (avg) Average airflow through each selected airway
Net Airflow (total) Airflow through entire mine network.
In most cases, only the Selected Airway costs and graphs will be relevant to the simulation results, however at times it is important to consider the effect of changing airway sizes on the rest of a mine.
For example creating a large shaft to deliver more airflow to a mine, may simply increase the cost of the airflow through other parts of the mine, offsetting some of the expected ventilation savings. For this reason, Total Network ventilation costs are included as a separate column and graph, and should be considered if the project is an addition to a mature mine.
Fixed or Fans ? |
When designing networks to a required flow, always use a FIXED flow for the airways being considered for financial analysis. Using FAN curves on selected airways, will result in decreasing flow for smaller airways, which in turn, despite increasing fan pressures, may actually result in a decrease in ventilation costs. There is no point in establishing an economic airway size if it does not deliver the required airflow.
HINT : The financial simulator tools may be useful for examining the airflow capacity of a particular fan on different airway sizes. Even if the financial aspects are irrelevant, the fan performance can be examined to test whether fan flows can be achieved over multiple airway options.
In some cases, a fan may be used where perhaps only one fan option is available, or where the effects of different airways sizes need to be examined on a particular fan performance and cost.
Simulates the steady state effects and spread of contaminants in the air.
Performs a contaminant simulation based on the position of contaminant source(s) placed in the network.
Upon completion, the view will switch to a contaminant view with airways coloured according to concentration of contaminants. Contaminant can be placed in a network by using the Edit toolbar function, or the Contaminant toolbar button. Contaminant strengths are entered proportional to the airflow they are placed in, and are considered dimensionless.
EXAMPLE Entering ‘100’ as a concentration value in an airway will result in the dilution of the value as uncontaminated air is mixed downstream. In this case, a value of ‘25’ downstream would indicated 25% of the original contamination strength..
The contaminants may be cleared by pressing the Clear button at the base of the contaminant sub-menu.
Determines the source of air at a specific location.
A sourcing simulation is similar to a reversed contamination simulation. It tracks airflow back from a placed contaminant source, and indicates the percentage of airflow which contributes to the airflow through the contaminant marker. This function is useful in determining where a location sources its fresh air from, or for analysing ways to reduce or increase airflow sources from certain areas (such as increasing airflow sourced from a bulk air cooler or decreasing airflow sourced from a production area.)
EXAMPLE Entering ‘100’ as a concentration value and performing an ‘air sourcing’ simulation will show which airways upstream are carrying the relative amounts into the original airway. Back tracking the concentrations to the surface will show which surface airways are providing the airflow and may show values such as (for example) 25% decline adit, 60% main vent shaft, 15% hoisting shaft.
Assist in finding the location of a contaminant source.
This simulation function was designed to assist in quickly identifying the possible locations of a fire or contaminant source (eg dust or production fumes) underground. As people report the status of air from different locations (for example smoky air or clear air), the simulation will colour airways upstream and downstream as either smoke (red), blue (clear) or yellow (possible smoke source)
Contaminant reports can be placed by selecting the location tool bar button under the contaminant button. A RED pin) can be placed to designate a contamination report. Ventsim will assume that all airways downstream from this report will also be in smoke (coloured red) and all airways above the report will be a possible source of smoke (marked in yellow). The BLUE pin indicates clear air. Ventsim will assume that all airways upstream from this point are in fresh air (coloured blue). Once reports are place, select the location simulation function to simulate and colour the airways around the reports.
As more reports are received, the YELLOW possible smoke source areas will decrease and the location of a fire or contaminant source can be narrowed.
EXAMPLE Mine Control receives a radio report that smoke has been smelled in a decline location. Checks reveal that other personnel further up the decline cannot smell any smoke.
The vent officer places a ‘REPORT SMOKE’ tag on the airway where smoke was reported and a ‘REPORT FRESH’ tag on the clear airways. Pressing LOCATION SIM will show the likely paths of the smoke in RED, what areas are likely to be fresh in BLUE, and what airways may be the source of the SMOKE in YELLOW.
After receiving two more reports of smoke in different areas and fresh air in other areas, the simulation suggests the smoke could only be coming from a workshop area in the mine. The vent officer directs emergency personnel to that area, who find a large number of smouldering rags in an industrial waste bin.
Example showing smoke and fresh reports helping narrow down a smoke source.
Displays a brief summary of your network collectively, or grouped under different TABS. The data may be copied to the clipboard, for pasting into another package such as Microsoft Word, or an email.
An example output is listed below from the Advanced version with explanations.
|
NETWORK AIRWAYS |
2772 |
Total number of discrete airways in a network |
|
Total length |
66196.0 m |
Total summed length of all airways |
|
Total airflow |
1025.5 m3/s |
Total airflow returned to the surface |
|
Mine resistance |
0.00164 Ns2/m8 |
Cumulative resistance of moving the total airflow through the mine |
|
POWER SUMMARY |
|
|
|
AIR (loss) Power |
1772.2 kW |
Total theoretical power required to move air through all airways |
|
INPUT Power |
3609.2 kW |
Total installed electrical power required to move airflow |
|
Consisting of .. |
|
|
|
9 fans @ |
3607.6 kW |
|
|
0 fixed press @ |
0.0 kW |
|
|
2 fixed flows @ |
1.6 kW |
|
|
|
|
|
|
Network Efficiency |
49.1 % |
Ratio of theoretical to installed power. Network efficiency will decrease as more fans are required to boost airflow through mine. Placing fans in series (ie boosting) accumulates fan efficiency losses at each stage of the fan. |
|
NETWORK FAN SUMMARY |
|
|
|
Fan Installations |
7 |
Total fan installation in network |
|
Fan Numbers |
9 |
Total number of fans in network |
|
Fan Sites Switched Off |
0 |
Fans turned off |
|
Fan Sites Stalled |
0 |
Fans operating at their maximum pressure |
|
Fan Sites Negated |
0 |
Fans running with no pressure added |
|
Fans running reversed |
0 |
Fans running in reverse (user selected) |
|
Total fan power |
3607.6 kW |
Total of all fan electrical power. The is calculated from fan shaft efficiencies, and motor efficiencies. The fan power is calculate from the fan power curve. If the curve is unavailable, it is estimated from the fan total efficiency curve. If this is unavailable, the default fan efficiency is used. |
|
HEAT & MOISTURE INPUT SUMMARY |
|
|
|
|
|
|
|
Diesel Sources |
0.0 kW from 0 sources |
Sources of diesel heat and contaminants |
|
Sensible Heat Sources |
0.0 kW from 0 sources |
Sources of sensible (dry) heat |
|
Linear (S) Heat Sources |
0.0 kW from 0 sources |
Sources of heat distributed along multiple airways |
|
Latent Heat Sources |
0.0 kW from 0 sources |
Sources of latent (vapour) heat |
|
Oxidisation Heat Sources |
0.0 kW from 0 sources |
Sources of oxidising heat |
|
Electrical Heat Sources |
3609.2 kW |
Sources of electrical heat |
|
|
|
|
|
Total Input Heat |
3609.2 kW |
Total heat input from man-made influences |
|
Total Strata Heat |
2885.1 kW |
Total heat input from heat dissipated from rock |
|
TOTAL HEAT SUMMARY |
6494.3 kW |
Summation of all heat |
|
Total Refrigeration |
0.0 kWR from 0 sources |
Refrigeration installations |
|
HEAT BALANCE TOTAL |
6494.3 kW |
Summation of heat minus refrigeration |
|
Moisture Point Sources |
0 |
Number of point moisture sources (such as conveyor dust suppression spray) |
|
Moisture Linear Sources |
0 |
Number of liner moisture sources (man made, such as decline dust sprays) |
|
Moisture Input as Latent |
0 ml/sec |
Summary of moisture added from latent heat sources (such as diesel engines and latent point sources) |
|
Moisture Airway Surfaces |
4404 ml/sec |
Summary of moisture evaporated from rock strata |
|
Network condensation |
0 ml/sec |
Summary of moisture condensed as water (normally in upcast exhaust shafts) |
|
MOISTURE EXHAUSTED |
4403 ml/sec |
Total moisture exhausted from mine. |
|
HEAT AUDIT |
|
|
|
Input heat below surface |
6454.5 kW |
Check to make sure heat exhausted from mine, is accounted for from summation of underground heat sources. |
|
Elevation adjustment = |
29.5 kW |
Adjustment due to inlet / exhaust elevation differences (auto compression) |
|
Differential inlet to outlet |
6469.9 kW |
Different between inlet from surface heat, and exhaust to surface heat |
|
Potential heat imbalance |
14.1 kW (0.2 %) |
Error between the underground inputs and the surface recordings |
|
Potential temp imbalance |
0.00 C degrees |
Potential error in temperature as a result. |
Heat Audit errors normally occur due to changing air densities during the heat simulation, not been reflected in slight changes in air and mass flow. This small error is corrected next time the simulation is run, however the next simulation also adds slight changes to density, and hence the error is never truly eliminated.
How much Heat Audit Error is too much? |
It depends on the network and tolerance for temperature margins, however up to 5% is generally acceptable, and will only give a slight imbalance in temperatures. Errors beyond 5% should be investigated to ensure major recirculation, or some other heat imbalance is not occurring in the model.
A selection of tools and settings to check, modify and fine tune the network
Displays a dialogue window which allows
editing, adding and deleting of all fans in the network fan database. Up to one
thousand (1000) fans and the associated fan curves may be entered into the fan
database. A display for each fan curve and data will be presented when a fan is
selected from the display list.
The copy and paste functions can be used to copy data to or from another program (for example a spreadsheet).
Caution should be taken when deleting or modifying a fan, as any network which may have used that fan number, will still attempt to use that particular number fan's data. If the data is not present, or is different, the network will not simulate properly.
The fan name is entered or chosen at the top from the pull down menu. To enter a new fan, select File > New
At a minimum, fan curve points for quantity and either fan static or total pressure must be entered for each fan. Other curve information such as efficiency and power can also be entered to assist Ventsim Visual™ in estimating fan power and heat.
Density |
Density is an optional parameter, which will be assume a default value if not specified. In Ventsim Visual™ Advanced, fan performance is adjusted for density changes in the mine. Most manufactures supply their fan curve at a standard density, however different densities can be entered for your fan curve if required.
Diameter |
Diameter is also an optional parameter describing the exit diameter of a fan. This may be the diameter of the fan casing or an evasé if fitted. Ensure the fan curve entered is for the specific fan configuration (check with your fan manufacture for this). Adding or removing an evasé from a fan for example can significantly change the fan static pressure curve (although the fan total pressure curve will remain the same). Where only a static curve is available, the diameter can help estimate fan total pressure and the associated power consumption.
Where only fan total pressure is entered, the fan diameter can help estimate available fan static pressure, an important consideration for surface exhaust fans. Finally, the fan diameter can also help estimate new curve points for the fan database, if either the fan static or total curve is unavailable. See the fan database section for more information.
Fan speed |
Fan speed can be individually changed at different fan locations, and will calculate the theoretical fan performance difference at different speeds. Note that this is a theoretical estimate only, and may become less accurate where extremes of fans speeds are used.
Fan Reversal |
ReverseP and ReverseQ modifies performance for fans run backwards for an emergency situation. Most manufactures will not supply these figures as fans are not generally designed to do this (although some fans can be designed to perform better in reverse than others). These figures ideally need to be derived experimentally be measuring actual fan performance with blades running in reverse. Ventsim Visual™ initially defaults to 0.5 for both (50% of maximum pressure and 50% of maximum airflow).
Comments |
Comment box is included to describe more information about the setup or configuration of the fan.
Point Table |
Fan Point Table : The table will allow direct entry of fan curve data. Fan curves will be constructed as data is entered. If points are submitted non-sequentially, the graph may initially look incorrect, however clicking on Consolidate Data Points, will automatically rearrange data points and fill in missing fan point data.
To calculate fan power within a network, Ventsim Visual™ needs either a fan efficiency curve or a fan power curve. If neither of these curves are available, the default fan efficiency will be used from the Settings menu. If both efficiency and power curves are entered, Ventsim Visual™ will preferentially use the fan power curve to calculate absorbed fan power.
Should I Use Static or Total Pressure ? |
Most fan manufactures supply one or both of the pressure curves. Ventsim Visual™ differs from Ventsim 3.9 in that it has an option in the Settings – Air Simulation menu to universally use fan total pressures (FTP), fan static pressures (FSP) or a mixture of both.
Using FSP curves will ignore the fan velocity pressure (FVP) portion contribution to network pressures, but will also ignore any system exit velocity losses to surface throughout the network.
Using FTP curves will include the FVP portion, but will include system exit velocity pressure losses as part of the network system total pressure.
More information is available in the Settings Chapter.
The case for Fan Static Pressure Simulation
It is technically correct for simulations to use fan total pressure (FTP) curves for fan installations. Fan total pressure however is not always converted into ventilation energy due to outlet losses from fan installation configurations.
Traditionally, Ventsim 3.9 has encouraged users to utilise fan static pressure (FSP) curves for modelling, (although FTP curve modelling was included as an option). Using FSP curves excludes the velocity (dynamic) component of fan pressure curve which is therefore assumed not to contribute to the overall system pressures in a network simulation. To partly offset the lack of velocity pressure inclusion, the system exit velocity pressures (the velocity pressure loss to the network from air exiting from shafts or other exhaust airways) are also not included by Ventsim 3.9 in calculating overall system pressure. While these two factors partially cancel each other out, using Static curves for underground fans is likely to give a slightly conservative system pressure and airflow if fan exit (shock) losses are modelled identically for both an FSP and FTP case.
When designing a network, this may be advantageous to provide contingency for design simulations. In addition, use of FSP curves is less reliant on accurately modelling fan exit shock losses, and provides a greater contingency for design airflow. In general, they may be more suitable to use for an inexperienced user.
The case for Fan Total Pressure (FTP) Simulation
FTP Simulation will allow Ventsim Visual™ to utilise the full fan total pressure curve for network system pressures. Provided fan exit shock losses are modelled to consider the fan installation and exit airflow orientation, then this method should provide more accurate results. In addition, as Ventsim Visual™ will consider system exit velocity pressures when FTP modelling is selected, fan exit diameters or airway surface exhaust sizes can be adjusted to simulate the effect of different evasé sizes on surface exhaust airways
Note: Increasing fan diameters (evasé) in Ventsim Visual™ for underground installed fans will have no automatic effect on network simulation results, as it will not change the surface velocity pressure exit losses. It may however decrease shock losses at the fan exit, which if modelled in Ventsim Visual™ by changing airway shock loss will result in improved fan performance.
In Summary
In most cases, if fan exit shock losses are modelled with the same factors, the FTP pressure method is a more accurate method and will deliver slightly more airflow through a mine. This may or may not be significant for your model and should be considered when examining the overall contingency built into the model.
Tools Menu |
The tools menu contains a number of functions to assist in estimating fan static or total fan curves if either one is unavailable. This may be required if only a Fan Static Pressure (FSP) curve is available, and you wish to simulate the network using a Fan Total Pressure (FTP) curve. Ventsim Visual™ will use the outlet diameter of the fan to calculate the velocity exit pressure of the fan, and thereby calculate the missing static or total pressure curve.
A list of elevation ranges on which airway data can be individually viewed.
A dialogue window is displayed which allows editing or creating of a list of levels (elevations) between which airway data is located. The level list can contain up to 1000 levels on which your network will be created.
Elevation data can be edited in any order, as well as added at a later date - Ventsim will sort the data from highest to lowest when next displayed.
To select which levels are displayed, choose the View Options toolbar button, Select Levels and click which levels you want to display. Alternatively, levels can also be independently set by using the mouse context pop-up menu (right mouse button on the screen) to Select Levels. Level can be chosen by clicking or fencing a range of elevations, and then Right Click the screen to commit those changes.
To view ALL levels at any time, simply use the Right Click pop-up menu to select All Levels.
Displays a list of currently viewed airways in a spreadsheet form.
A READ ONLY spreadsheet of airway data is displayed which can be copied and pasted to other applications such as Microsoft Excel or Word.
Up to 70 different types of data can be displayed on the spreadsheet, however Ventsim Visual™ initially defaults to only around a dozen different types. To display more data types, use the DISPLAY menu to select which data you wish to display.
Data can also be removed from the spreadsheet, by selecting EDIT > REMOVE or using the right mouse button. Data columns can be reordered by selecting the column title and dragging to a new location. In addition columns can be resized and resorted by using the appropriate menu commands.
Simplify allows the user to reduce the number of airways in a network to a more efficient number without affecting the overall network analysis.
It is particularly useful where a network has been imported via a DXF file and contains a large number of very detailed but unnecessary small connected airways.
Simplify will search a network for sequences of airways that may be reduced to a single straight airways. In doing so, much of the overhead and effort required to set parameters to every airway can be reduced. Note that the simplify function will only combine airways that have a single entry and exit. Airways at junctions and split branches will remain untouched.
Simplify Example : Note in the above example, 10 airways are simplified to 6 airways without affecting the integrity of the network.
The simplify dialog box allow the user to alter the way that airways are simplified.
Maximum Angle |
The Max Angle option specifies the maximum angle between two airways being considered for merging. For example, if the original network contains a number of airways that form a curve and Max Angle is set to 20 degrees Simplify will keep on merging airways until the airways being considered have directions changed by 20 degrees or more.
Maximum Angle |
The Max Length option restricts only airways with lengths up to the value length from being combined. For example if set to 30m, only airways with lengths of less than 30m will be considered for merging and simplifying.
In general, the higher the values of the Max Angle and Max Length settings, the more aggressively Ventsim Visual™ will seek and combine airways.
Use combined lengths: |
Ensure the new length of a combined airway is fixed to remain exactly the same as the original combined lengths even if the original airways formed a curve. If not set, the new lengths will be recalculated as the true length of the new straight line.
Ensure no resistance presets filtered: |
Ensures that airways with a preset resistance (such as a bulkheaded airway) are not simplified and merged with other airways.
Ensure airways dimensions are the same: |
Check to see if airways that are considered for merging and simplifying are only joined if they are exactly the same size.
Ensure wall types are the same: |
Similar to dimensions, only airways with similar wall (friction factor) types are joined.
Selected airways only: |
Only simplify selected airways and ignore all others.
Remove airways with zero flow: |
Remove airways with no airflow – ensure these airways will not be necessary for future simulations before removing them.
Modify a selection of airway specific parameters
Lengths |
Fixes or un-fixes airway lengths, so that networks may be manipulated without changing the calculated airway lengths.
Fix All Lengths |
This will fix and protect all airways in the network from changes in length when moving airways. This may be useful if airways are required to be moved for clarity, but lengths must remain the same.
Unfix All Lengths |
This will un-fix and recalculate all airway lengths in a network.
WARNING - This function will recalculate airways lengths and hence change any previously fixed lengths. If there are any doubts, use the EDIT function to individually fix/unfix lengths of only the airways that need to be changed.
Swap Eastings / Northings |
Reverses the Easting and Northing coordinates. This may be useful where the coordinate system in Ventsim Visual™ does not match the directions used on the Mine Plan Grid. Where the direction of the coordinates needs to be reversed, use the SETTINGS > COORDINATES settings to change direction of the axis coordinates.
Auto Name |
Automatically places a code number on every airway without a current airway name. A letter may be specified to head the number if desired (eg B157).
Limit Display Data |
Helps reduce text data shown on screen.
This function search selected airways (or if no selection made, all airways) for continuous airway segment groups without junctions, and limits data display to only one of those airways. When the menu item TEXT DATA > LIMIT DISPLAY is selected under the VIEW menu, the display will only show text data on the single airway segment.
HINT As many continuous airway segments show similar data (such as airflow amounts), reducing text display to just one airway per segment group can significantly reduce text clutter on the screen. If the automated function does not select the desired airway to show the data, simply EDIT the desired airway an check ALWAYS SHOW DATA.
Resequence Index/Unique Numbers |
Resequences the order of airway numbers in a Ventsim Visual™ network.
Index numbers are dynamic numbers representing airways stored internally in Ventsim Visual. The numbers may change as airways are deleted or added. Ventsim Visual™ uses Index numbers to refer to airways during simulation and when indentifying problems. All index numbers are sequential and the highest index number will be the sum of all airways. Resequencing index numbers renumbers all airways from higher elevation to lowest elevation, easting to northing.
Unqiue numbers are static numbers which do not change when airways are deleted or added. Numbers are sequenced incrementally from the last highest unique number. As such, as airways are added and deleted, there may be large gaps of numbers between airways. Unique numbers are a useful reference to identify the same airway as the network is developed. Resequencing the unique numbers, renumbers all airways from number 1, sequentially to the last airway.
HINT Resequencing numbers is not a requirement in Ventsim Visual, but may simplify tracking airways, as the resequence function tends to group airways in similar airways with similar numbers. This is particular handy in the SPREADSHEET function which initially lists airways in sequential index order.
This option allows detailed checking of networks, and will identify areas of your network that may cause problems during the simulation process. A network with too many redundant bulkheads (bulkheads in the same airway path as other bulkheads), or fans that are in the same airway path as other fans, may result in a network that will not converge.
Restrictive Fans: |
Finda and alert the user to fans that are directly competing against other fans.
Unnecessary Bulkheads: |
Finds and if desired remove bulkheads that are not necessary (usually because another bulkhead in the same airway has already stopped the airflow).
Reset Network |
Removes all airflow and temperatures from a network. The simulation processes is restarted with fresh data. Ventsim Visual™ utilises flows, densities and temperatures from previous simulation to help it to recalculate new simulations faster and more accurately. If data has been corrupted during a bad simulation (which may have produced errors, excessive airflows, heat or densities), this may hinder subsequent simulations from finding an acceptable solution, or may simply produce further errors.
Resetting the network will remove all calculation flows, pressures, densities and heat. It will NOT remove any values fixed by the user, such as fixed flows, pressures or heat sources.
Conversions |
Sets the metric and imperial conversion units and factors used for Ventsim Visual, as well as the number of decimal points to show on the display.
The conversion table displays the metric and corresponding imperial units for each type of data used in Ventsim Visual. The table is saved with every network, and can be individually modified for each network file. The conversion settings can be inherited by other networks or saved in a template file.
The imperial unit names and factors may be freely changed to suit the region or preference of the mine. The imperial column in the table may even contain metric units if required, by setting the imperial unit name to a metric text value and a conversion factor of ‘1’.
Decimals |
Sets the number of decimal units to display on the screen and in text displays.
Example A value of three (3) for example will display a value of 23.123 on the graphics display, or in the spreadsheet view.
Caution While the metric unit text name can be changed, the underlying metric value cannot be changed. For this reason, the units must remain the same as preset in Ventsim. For example, the Velocity cannot be changed to km/hr as this would represent a different value scales, and the underlying Ventsim equations are hard corded to use m/s.
Imperial Unit |
A text name describing the imperial units.
Multiplier |
The factor used to convert from metric to imperial. Ventsim Visual™ performs all internal calculation using metric formula and methods, converting displayed data back to imperial (if set in SETTINGS). The factor is used to convert to and from metric to imperial, and will result in errors if not properly set.
Addition |
This factor is only used in converting degrees Celsius to degrees Fahrenheit, and added to the metric value before multiplied in imperial.
An extensive list of settings used by Ventsim Visual™ that controls the behaviour, simulation parameters and visual appearance of the program.
Settings are divided into a number of categories, including.
|
Category |
Description |
|
Airway Defaults |
Controls parameters of the simulation process for airflow |
|
Colours |
Colours of the background and text used for display |
|
Graphics |
Visual appearance of graphics, sizes of objects and text on screen |
|
Heat Physicals |
Actual parameters of air and rock conditions used in simulation |
|
Model Coordinates |
Coordinates and grid systems used for the network |
|
Simulation – Heat |
Controls parameters of the simulation process for heat |
|
Simulation – Airflow |
Controls parameters of the simulation process for airflow |
|
Ventsim Main |
Tbe program control settings |
For further information on setting, go to the settings sections
Fits all display data on the screen.
Increase the distance away from the window point of focus. This may be of use if the mouse used does not have a scroll wheel.
|
Chapter 5 |
Default size of new airways. Imported DXF and text files without specific airway size will also be set to these values
Primary Secondary Layer |
Default view layers to set to new airways
Default efficiency factor to apply to power calculations for fixed quantities and fans without efficiency curves.
Default fan motor efficiency to apply to calculated fan shaft power to estimate the electrical power absorbed by the fan motor. In most cases it will be around 95% for direct drive electrical motors, or as low as 80 – 85% for offset or gear drive fans.
Friction Factor |
Default friction (K) factor to apply to new airways
StopResistance |
Default resistance to apply to blocked (stopping) airways. This number should always be high to limit flow of leakage air.
AirwayShape |
Default shape of airway.
ShowAllData |
Unused at this time
Grid Colour |
Colour of grid lines.
Grid Sheet |
Colour of semi-transparent edit plane sheet shown during vertical drawing operations.
Background Colour |
Colour of upper and lower halves of background. The colours are smoothly blended to provide a gradient effect. Lighter colours may be more appropriate for presentations and report.
Size Data Node Airway Text |
Size of airway text displayed on model. Larger text sizes are generally clearer to read, however excessive data may clutter display.
Text2DSolidMode |
Text display defaults to a pseudo 3D mode which show text as horizontal labels which move dynamically with airway positions. Setting to False presents a different method of displaying airway data on branches. Data is imprinted into the airway sidewall and rotated and scaled with the airway model. In some circumstances it may or may not improve legibility.
Size Node Icons/Arrows |
The size of the nodes, icons and arrows. Note that the size reduces in wireframe mode to improve display legibility.
The range of elevation to show around a single selected level. Selected levels may be chosen from the RIGHT CLICK mouse popup menu, and limit the range of airways data shown on screen.
Transparency Flag |
[TRUE] Completely hides airways outside the display range.
[FALSE] Airways outside the display range are shown as semi-transparent. The level of transparency can be adjusted from the Colour Manager.
Opaque |
The default level of transparency for transparent airways. This can be adjusted in the Colour Manager
Dimming |
The relative colour of transparent airways. Lower value will make transparent airways darker.
Size Node Icons Arrows |
The size of the nodes, icons and arrows. Note that the size reduces in wireframe mode to improve display legibility.
TextTransparent |
[TRUE] Text labels backgrounds are transparent and show graphics under the label.
[FALSE] Text label backgrounds are solid and do not show graphics underneath. In some cases, this may improve the legibility of text.
TextScaleRelative |
[TRUE] Reduces the size of text labels relative to distance away from view camera. This make close airways larger and more legible and distant airway text smaller.
Rotation Inertia / Damping |
Ventsim model rotation results in a short period of continued rotation after the mouse is released. This is purely for visual appeal and is provided to give models the illusion of ‘weight’ and solidity. The speed at which rotation is damped can be adjusted or turned off using these settings.
HINT To allow the model to rotate freely without stopping, choose a damping level of zero (0).
Anti-aliasing |
An advanced graphics option (not supported by all graphics card) which smooths the appearance of the edges of solids to give a visually more appealing look. The option may significantly slow some graphics cards or cause graphics irregularities. By default, it is set to FALSE.
Set to FALSE Set to TRUE
Simulation airflow settings directly influence how the airflow simulation operates.
Allowable error |
Defines the level of accuracy Ventsim must resolve down to before an acceptable solution is displayed. This should normally be set to less than 0.1 m3/s error. If a final analysis is required it may be advisable to set this to 0.01 m3/s or lower. The smaller the value, the more accurate the simulation process, but the longer it may take.
Iterations |
Sets the number of attempts Ventsim Visual™ can take to achieve an acceptable error, before the program abandons the simulation process.
FanReversePFactor, FanReverseQFactor |
Defines the default reverse fan performance relative to the original fan curve for the pressure and quantity of a fan running in reverse. These factors decrease the performance of fans set to run in reverse (for emergencies for example) in the EDIT box. Note that the default values may be overridden by values directly placed in the Fan Database for individual fans.
Autosimulation |
Automatically performs an airflow simulation after every modification to a network. This will conveniently display airflow amounts and directions without having to simulate the network. For large networks, or networks undergoing extensive modifications, it may be preferable to turn this function off, as it will slow down editing and view functions.
WarnOnChangeDirection |
If set to TRUE, Ventsim Visual™ compares airway directions before and after a simulation and alerts the user which airways have airflow that have changed direction during simulation.
Compressible Airflows {Advanced Version] |
Use compressible airflow simulation techniques.
Compressible airflow has a significant influence when simulating deeper mines. In deeper mines (greater than 500m) or when heat simulation is used, it is recommended that compressible airflow be set to True.
When set to True, Ventsim Visual™ will assume compressible air, and adjust air densities, volumes and fan curves according to airway depth and corresponding density. In the Advanced version, temperature effects on density are also taken into account when Heat simulation is run in conjunction with air simulation.
Airflows and fan curve performance after simulation is shown according to the density of air at the location of the airway.
[TRUE] Ventsim Visual™ will ignore all warnings related to No Entry or No Exit errors found during simulation (airways with no other airways joining)
[FALSE] Ventsim Visual™ will only ignore airways which have been set to Allow Open End in the Edit box. Any other ‘orphaned’ airways will cause the simulation to halt.
Specifies the fan pressure simulation method to use. Ventsim has historically allowed use of a combination of static and total pressures to simulate air flow through underground and surface fans. To maintain compatibility, this option has been kept, however two alternative methods are presented.
Total Pressure Method |
The use of fan total pressures is considered the technically correct method for simulating airflows. All fan curves in the fan database must at least have a total pressure component. If only a fan static pressure curve is available an error will be raised during simulation. Ventsim Visual™ can help predict a fan total pressure curve from an existing static pressure curve using tools in the Fan Database Editor.
The total pressure method assumes the full fan total pressure is available to ‘motivate’ air through a mine. The method also considers system velocity pressure losses to the atmosphere (for example exhaust shafts) and incorporates these into the simulation. The fan total pressure method relies on the user accurately considering fan exit losses with appropriate shock loss factors and resistances, as total fan pressure is rarely fully available to deliver pressure to network air flow. Fan outlet configuration, outlet flow direction changes and the inclusion of evasé s (which boost static performance and reduce exit shock losses) or other exit devices such as fan shutters need to be fully considered if they have not been incorporated into the fan curve, otherwise the network may over predict the available pressure and flow.
Static Pressure Method |
A more traditional approach is to use fan static pressure, which assumes that fan velocity pressure is wasted and does not contribute to the system ventilation pressure and flow. While this is not technically correct, this assumption removes some of the criticality of defining accurate exit losses, and while exit losses should still not be ignored, the resulting simulation will provide a more conservative result to simulation estimates of pressure and flow. The Fan Static Pressure (FSP) method also ignores system exit velocity pressure losses. For a primary (surface) fan driven network systems, there is negligible difference between the FSP and FTP methods (as the FTP methods considers velocity pressure losses as part of the system pressure), however where underground booster fans contribute to a significant portion of ventilation flow, the difference between the two methods will increase.
To use this method, all fan curves used from the database must have a static pressure component. If only a total curve is available an error will be raised during simulation. As with the FTP method, the fan database form has tools to assist the user in estimating FSP curves if not available.
Mixed Pressure Method |
The mixed pressure method maintains compatibility with Ventsim 3.9, which allows both pressure types (static and total) to be used for fans in networks. The mixed pressure method is similar to the static method, in that it does not considerer system velocity pressure exit losses. Fan pressure curve types can be specified for each fan location in the network. This may be of assistance if some static or total pressure curves are not available for the fan, and the user does not wish to estimate a curve. The mixed pressure method is considered to be the least consistent method to use, and should be avoided if possible. In particular, the use of fan total pressures for surface exhaust fans will overestimate the performance in a network as the system velocity pressure losses will not be considered
Ventsim 3.9 networks will be automatically imported into Ventsim Visual™ as a ‘mixed pressure network’. It is recommended for consistency, the network be either set to a StaticMethod network or a TotalMethod network. Some fan curves may need to be modified to allow this to be done.
Adjusts settings which directly influence how the heat simulation operates.
Heat DivisionsMin/Max |
Airway segment divisions for heat calculations.
The heat simulation process in Ventsim Visual™ progressively calculates heat affects along each airway by dividing it into sections. When a rapid change takes place or where the airway is very long, this allows the psychrometric process to continually adjust pressures, temperatures and moisture content, resulting in a more accurate estimate. Ventsim Visual™ automatically adjusts the number of divisions according to airway length and heat inputs. The number of divisions used is restricted by the min and max values in the settings. Higher division values will theoretically give more accurate heat estimates but will increase the time required for simulation.
MultiHeatIterations |
Performs multiple airflow and heat simulations.
When set to more than one (1) performs multiple heat and airflow simulations, adjusting densities and airflows between each simulation. Manually pressing the HEAT simulation button has the same effect.
Heat simulation in Ventsim Visual™ Advanced is performed as two discrete simulations, first as an airflow balance, followed by a heat balance simulation. While the mass flow balance from the airflow simulation is kept constant during heat simulation, the new temperatures and air densities calculated after heat simulation, result in a theoretical mass imbalance of airflows. This can be corrected by a subsequent airflow simulation; however subsequent heat simulations will again affect the balance. This imbalance normally reduces with subsequent simulations, as temperatures and airflow changes reach equilibrium.
Multiple pass iterations can be set which will automatically force Ventsim Visual™ to simulate the network a number of times, to account for some of the potential imbalance. This will significantly slow down simulation time. iteration values larger than one are usually unnecessary if a network has already been heat balanced, or if the HEAT simulation button has already been pressed a number of times.
HINT Performing a multiple pass heat simulation may have value if the network shows some heat instability (changes in temperatures between simulations). Heat instability is normally caused by unstable natural ventilation changes driven by conflicting changes in airflow and heat
For example a heat source which causes an increase in temperature may cause an increase in airflow due to natural ventilation – in subsequent simulations, the higher airflow causes lesser temperature increase from the heat source, which reduces the airflow due to natural ventilation. The process may then oscillate between solutions for each Heat simulation. As a final pass performing a multiple pass simulation of 10 or 20 (which may take a long time) may help resolve this instability
Ignore HeatBalanceErrors |
Extreme changes in airflow temperatures along airways or at junctions may create difficulties for Ventsim Visual™ to calculate the new psychrometric properties in an acceptable number of iterations. Normally the error is small and may be resolved during the simulation process as surrounding airways are adjusted, and the degree of change is reduced in subsequent iterations.
Setting this value to TRUE allows the simulation process to ignore imbalances and continue towards an acceptable solution.
CAUTION : Allowing heat balance errors to be ignored may propagate an extreme heat balance error along other airways. This will normally result in the simulation process halting due to other heat related errors (such as over-temperature). For this reason, unless there are continued heat balance issues, it is recommended this normally be left as FALSE unless all other options to resolve a poorly simulating network are explored first.
Water to Diesel Ratio |
For diesel heat sources, this value defines the amount of water emitted to the air as latent heat is per unit weight of diesel fuel consumed. Although the theoretical combustion reaction portion of water produced to fuel consumed is only around 1.1, the operation of a diesel machine in a mine environment results in a greater release of water into the air due to accelerated evaporation of water around the machine (from a wet roadway or walls for example), compounded by other sources such as handling of moist or wet material, wet exhaust scrubbers and cooling systems used by the machine, result in a much higher value. A value of five (5) or more is generally recognised as giving a more realistic result for water introduced to the air by mobile machines. Stationary machines may be closer to the theoretical value.
The default water to diesel ratio is used on all diesel sources in the network. To use values other than default, the sensible and latent heat will need to be entered separately instead of a single diesel heat source.
Diesel ParticleEmmisions |
Describes the default amount of diesel particles emitted from a diesel engine, per unit of diesel engine power. This value is applied to diesel heat sources placed in a network, to assist in diesel particulate matter (DPM) simulation for the model. The value is highly dependent on the type of diesel engines, catalytic converters and scrubbers being used on the engine, as well as the type of diesel fuel used. In most cases, tests will need to be done on engine exhausts, or information gained from diesel engine manufacturers to find the correct value to use. Ventsim Visual™ currently uniformly applies this value to all diesel heat sources.
Temperature Limit |
The temperature limit above which Ventsim Visual™ will halt simulation and display an error if it occurs. Temperature limits can be exceeded when too higher heat input is placed in an airway with not enough airflow.
Heat simulation uses a number of empirical formulas which are designed to work within a specific temperature range. In general, temperatures above 70 degrees centigrade will start to result in a reduction of accuracy of heat estimation.
Mass FlowLimit |
The minimum mass flow that Ventsim Visual™ will perform a heat simulation on. Below this limit, Ventsim will assume the air is stationary, and adopt the local virgin rock temperatures as the air temperature. This value must be set above zero, as portions of the program which calculate heat and moisture derived from rock surfaces must have some airflow velocity to work. While there is some potential for heat imbalance errors by not taking into account low flow airways, it is generally small due to the limited heat energy flow able to be carried by these low flow airways.
Use NVPressures |
[TRUE] Forces Ventsim to calculate natural ventilation pressures derived from air heat and density in the underground network. Natural ventilation pressures can sometimes produce unstable simulation air flows due to dynamic changes in airflow affecting subsequent heat balance simulations. This is discussed further in the Heat Simulation section. If this problem impacts heat simulation, it is suggested to set to it to False to produce a stable simulation.
[FALSE] Ignore natural ventilation pressures. Where heat simulation is not required, or natural ventilation pressures are not likely to be significant in a mine, it is suggested that this setting be set to FALSE.
Heat Iterations |
Limits the number of internal iterations permitted by Ventsim Visual™ to converge and find an acceptably balanced heat solution. Where recirculation occurs or large numbers of very low airflows are present, a simulation may take a large number of iterations to fully balance. In most cases, the main airflows will quickly balance, and even if the simulation fails to complete within the set number of iterations, this will usually be in the low flow airways which have little effect on the main flow airways. The status bar at the base of the Ventsim Visual™ window will show the progress of a heat simulation, including the number of iterations and the heat balance errors. Increasing the number of iterations may help resolved unbalanced networks, but will take longer to simulate.
HINT A leading cause of heat flow convergence issues is recirculating airways in low flow airways due to natural ventilation pressures. Naturaly ventilation pressures can create internal ‘eddies’ of air in disued or low flow airways which can affect heat simulation convergence. To prevent this, and speed up heat simulation, either turn off natural ventilation simulation (if natural vent pressures are not significant) or block disused airways so they simulate as no flow.
Temperature Accuracy |
Sets the temperature balance limit Ventsim Visual™ must achieve for all airway mixing at junctions in a network, to consider a simulation as balanced. If the balance is not achieved for EVERY airway and junction, iteration is performed until the iteration limit is reached or temperatures are resolved.
HINT The smaller the temperature accuracy set, the longer a simulation may take to complete. In most cases, the vast majority of airways will fall well under this limit, and any temperature accuracy issues will be limited by very low flowing airways which have little impact on the main network.
Maximum HeatInput |
Limits the amount of heat that can be put into a single airway. This is mainly included as a check to ensure excessive heat is not placed in an airway (such as a point heat source value accidently being entered as a linear heat value).
The environment factors describe values used by physical items within the network. They are critical to identify the base starting points of a ventilation simulation, or providing default air or heat simulation parameters to airways that do not have specific values set.
SurfaceElevation |
The elevation (or ‘reduced level’) where a specified point in the mine exits the surface. All other surface related settings (such as surface temperatures, pressures and rock temperatures) are assumed to be at this elevation.
If this value is set to zero (0), Ventsim will search and use the highest point in the network.
SurfaceRockTemp |
The temperature of virgin rock at the Surface Elevation. Virgin rock temperature underground are calculated from this base by using the Geothermal Gradient.
CurrentYear |
The calendar year at which the simulation is taking place.
Ventsim Visual™ uses this value to calculate the age of an airway underground, if the individual airway age is entered as a calendar year (such as ‘2005’ in the EDIT box). Where an airway age is entered as a time value (such as ‘3.5’ years), the CurrentYear value is ignored.
HINT Where true airway ages have been entered as calendar years within a network, the CurrentYear setting is useful for ‘ageing’ a mine and determining future cooling requirements. Heat input or ‘flux’ from virgin rock strata decreases exponentially over time as the rock is cooled, and future cooling requirements can potentially be lower than current cooling requirements as a result.
GeothermalGradient |
The rate at which rock increases in temperature at depth. This is assumed to be a linear value. Geothermal gradients show significant differences at different points around the earth, and can be as low as 1 degree Celsius per 100m to more than 10 degrees Celsius per 100m. This value should always be adjusted to suit the conditions at or near your mine.
HINT In rare cases, the temperature gradient may not be close to linear, particularly in near surface portions of the mine. The best approach is to calculate to gradient over the main underground portion of the underground mine (which a subject to the majority of heat influence), and project this temperature gradient to the surface. Enter the ‘SurfaceRockTemp’ settings as this calculated value, not the true surface rock temperature.
|
Orebody Type |
Degrees C/100m |
Degrees F/100ft |
||
|
|
Min |
Max |
Min |
Max |
|
Copper Ore body |
2.5 |
7.7 |
1.4 |
4.2 |
|
Carboniferous |
2.0 |
5.0 |
1.1 |
2.7 |
|
Clays |
3.3 |
3.3 |
1.8 |
1.8 |
|
Limestone |
1.8 |
1.8 |
1.0 |
1.0 |
|
Sandstone |
1.7 |
3.3 |
0.9 |
1.8 |
|
Dolerite |
3.0 |
3.0 |
1.7 |
1.7 |
|
Quartzite |
0.8 |
1.5 |
0.5 |
0.8 |
|
Potash Low Grade |
1.3 |
1.7 |
0.7 |
0.9 |
|
Potash High Grade |
0.8 |
1.3 |
0.5 |
0.7 |
|
Hailte Low Grade |
1.4 |
4.0 |
0.8 |
2.2 |
|
Halite High Grade |
1.0 |
1.4 |
0.5 |
0.8 |
Table – Examples of Geothermal Gradients found in areas around the world.
AverageAge |
The Default Age of an airway opening in years. Airways without a specified age set in the Edit Box, will be assigned this airway age. Establishing airway age is important to all Ventsim Visual™ to calculate heat flow into an airway from geothermal heat. Geothermal heat flow decreases with airway opening age.
Wetness Fraction |
The default fraction of airway rock surface that is wet. Nearly all rock surfaces underground emit some degree of moisture. The wetness fraction defines what percentage of rock surface is considered wet. A value of 0.01 would define a very dry airway, while a value of 1.0 would define a fully wet airway. This value will be assigned to airways without a set wetness fraction from the Edit Box, and directly affects the amount of moisture available for airflow to evaporate and hence humidify the air.
Rock Density |
The default density of rock underground. This value is applied to an airway, if it has not already been set in the Edit Box. Rock density is a property which describes the mass of rock per unit volume. Rock density underground is used by Ventsim to calculate the directly related thermal diffusivity of rock material, if the diffusivity has not already been yet. Rock Density is not required if thermal diffusivity has already been set. If this value is changed, the user will be prompted to allow Ventsim to auto calculate the rock diffusivity.
RockSpecificHeat |
The default Specific Heat of rock underground. This value is applied to an airway, if it has not already been set in the Edit Box. Rock Specific heat describes how much heat must be absorbed or emitted to raise or lower the rock temperature.
Thermal Diffusivity |
The default Thermal Diffusivity of rock underground. This value is applied to an airway, if it has not already been set in the Edit Box. Rock Thermal Diffusivity is a property which describes the ability of rock to diffuse or transmit contained heat over a unit area per unit of time. In summary, rock with high thermal diffusivity more rapidly adjusts its temperature to that of the surroundings, because it conducts heat quickly in comparison to its heat capacity or 'thermal bulk'. Because diffusivity is directly related to density, thermal conductivity and specific heat by formula, rock thermal diffusivity is required when underground rock density has not been set. If this value is changed, the user will be prompted to allow Ventsim to auto calculate the rock density.
Rock Thermal Conductivity |
The default Rock Thermal Conductivity.. This value is applied to an airway, if it has not already been set in the Edit Box. Rock Thermal Conductivity is a property of rock which describes the ability of rock to transmit heat through itself.
Surface Wetbulb Drybulb |
The Default Surface Temperature Conditions of air entering a mine.. All air intake into the mine is assigned the default surface temperatures. The temperatures and Surface Barometric Pressure are used to calculate the surface air density.
HINT: In rare cases, a mine may have multiple intake airways with a range of elevations so great that different temperatures may be present at each intake. As the Surface Barometric pressure is defined for a single Surface Elevation, Barometric Pressures will be correctly recalculated for differing intake elevations; however temperatures may need to be manually corrected. Temperatures can be adjusted by place a heat or cooling source at the inlet of intakes to produce differing temperatures.
Surface Pressure Barometric |
The Barometric Air Pressure at the Surface Elevation.. The surface barometric pressure is important as Ventsim Visual™ calculates mine air densities from the surface barometric pressure and wet and dry bulb temperatures.
|
Rock Type |
Thermal conductivity |
Specific Heat |
Thermal Diffusivity |
|
|
W/mC |
J/kgC |
m2/s 10-6 |
|
basalt |
1.80 |
840 |
0.74 |
|
coal |
0.33 |
1300 |
0.20 |
|
dunite |
4.30 |
820 |
1.64 |
|
gabbro |
2.10 |
800 |
0.97 |
|
gneiss |
2.90 |
800 |
1.29 |
|
granite |
3.00 |
790 |
1.41 |
|
limestone |
1.30 |
840 |
0.64 |
|
magnetite |
4.41 |
600 |
2.10 |
|
marble |
2.60 |
880 |
1.18 |
|
quartite |
5.25 |
800 |
2.43 |
|
quartzite |
3.00 |
800 |
1.39 |
|
rock salt |
4.48 |
880 |
2.04 |
|
sandstone |
1.70 |
920 |
0.71 |
|
shale |
1.23 |
850 |
0.55 |
Table – Metric Examples of Airway Rock Physical Parameters
|
Rock Type |
Thermal conductivity |
Specific Heat |
Thermal Diffusivity |
|
|
Btu/h/ftF |
Btu/lbF |
ft2/h |
|
basalt |
1.04 |
0.20 |
0.029 |
|
coal |
0.19 |
0.31 |
0.008 |
|
dunite |
2.48 |
0.20 |
0.064 |
|
gabbro |
1.21 |
0.19 |
0.038 |
|
gneiss |
1.68 |
0.19 |
0.050 |
|
granite |
1.73 |
0.19 |
0.055 |
|
limestone |
0.75 |
0.20 |
0.025 |
|
magnetite |
2.55 |
0.14 |
0.081 |
|
marble |
1.50 |
0.21 |
0.046 |
|
quartite |
3.03 |
0.19 |
0.094 |
|
quartzite |
1.73 |
0.19 |
0.054 |
|
rock salt |
2.59 |
0.21 |
0.079 |
|
sandstone |
0.98 |
0.22 |
0.028 |
|
shale |
0.71 |
0.20 |
0.021 |
Table – Imperial Examples of Airway Rock Physical Parameters
Warning – These are examples only. Rock characteristics vary widely for different rock types and locations. Where possible, characteristics should be measured by laboratory analysis.
Ventsim Main settings control over-arching settings which influence all parts of the program.
Unit Type |
The type of units to use in Ventsim Visual. The program operates natively in SI Metric, with underlying calculations performed in metric units. To display imperial values and accept imperial input, set the unit type to Imperial. The imperial setting uses a conversion table to calculate the conversion from metric, and can be customised to suit mine preferences.
Warning – the conversion table has set limits of decimal accuracy to convert from metric to imperial and back again. If the decimal accuracy is too low, some accuracy may be lost in the conversion process, and the value input as an Imperial number, may be returned slightly differently.
Power Cost |
The cost of power supplied to the mine. The power cost is used to calculate the ventilation cost of running a mine network, and is applied to all fans, fixed quantities and fixed pressures.
Maximum AirwayNumbers |
The amount of memory to reserve for airways and graphics. Ventsim Visual™ reserves memory and resources for a defined number of airways. Reserving large numbers of airways will slow down graphics and simulation slightly. It is recommended to reserve only the number of airways actually required for the size of your network. If your network exceeds this number, Ventsim Visual™ will automatically adjust the setting to suit the higher number.
AutoBackup |
Forces Ventsim to make a backup of the currently worked network every 5 minutes. If the program crashes, or is forcibly exited, the backed up network will be loaded automatically next time the program is run.
Warning – if the network has become corrupted for some reason, there is a possibility that the auto-saved network may also be corrupted. For this reason, it is recommended that a network be regularly saved to ensure that good working copies are available as backups if required.
|
6 |
The toolbar allows quick access to commonly used Ventsim Visual™ functions.
The toolbar will be slightly different between Ventsim Viewer, Standard and Advanced versions.
Creates a new file. The current file will be cleared.
Open the file dialog to load a new file
Saves the existing file. If no name has yet been set, a Save File dialog will be displayed.
Copies selected airways onto the Windows clipboard. The airway can then be pasted into a different network.
Pastes the airways in the Windows clipboard, back into the currently loaded network. Note thast multiple instances of Ventsim Visual™ can be loaded, and the airways can be pasted into another instance of Ventsim Visual.
Reverses the last action performed in Ventsim Visual
Cancels to previous Undo, restoring any changes made.
Searches for specific items within a ventilation network. Pressing the ‘searchlight’ icon directly, repeats the previous find action. Pressing the submenu arrow next to the icon, activates the find submenu as shown below.
Name |
Find the name of an airway name or node. Entering any part of the name will find airways containing the name part.
Number |
Find an airway with the specified index or unique number
Fans |
Find airways with operating fans, fans that are turned off, or fans that are performing outside of their rated fan curves.
Fixed |
Find airways with fixed flows or pressures.
Heat sources |
Find airways with artificially heat, cooling, diesel or moisture sources.
Contaminants |
Find airways with contaminant sources set.
Errors |
Find network errors defined during the previous simulation.
Limits the data types shown in the adjacent pull down menu, to the category type specified.
Airflow |
Show data types such as air flow volume, velocity, mass flow and density
Pressure |
Shows pressure related data such as relative to surface, barometric and friction loss.
Attributes |
Shows airway resistances, friction factors and shock loss numbers
Energy |
Shows power and cost calculations for airflow, fan and fix inputs
Heat |
Shows heat related data, such a temperatures, internal heat content, humidity.
Identifiers |
Show airway specific indentifying traits, such as index or unique numbers and primary and secondary layers numbers
Contaminants |
Shows airway contaminant factors, source values, simuliated values, spread times and diesel particulate levels.
Rock |
Show airway rock conditions, such as wetness fractions, specific heat and other rock parameters.
Measured |
Not currently used.
Displays screen data of the type specified in the pull down menu.
Warning: some data types (such a pressures) may not be correctly set until after a successfully simulation. While Ventsim Visual™ records previous simulated values in a saved file, these values may not be valid if further changes and modifications have been made to the network.
Places the program in view mode
Left Mouse Drag |
Draw a window to zoom into part of a network. The front most airway in the view window will define the point of focus for the zoomed in area. To zoom into area behind other airways, ensure the zoom window does not contain any portion of the front airways.
Left Mouse Click |
Edit the airway. Left clicking the mouse on top of an airway will show the Edit Box for that airway.
Middle Mouse Drag |
Press and hold to pan the screen horizontal around the current Edit Plane
Click to centre the Edit Plane and rotation point about a specific airway or point on the Edit Plane.
Right Mouse Click |
Rotate the network graphics about the the point of focus. Hold and move the mouse vertically to tilt the network. Hold and move the mouse horizontally to spin the network.
Places
the program into draw (add) mode to allow creation of new airways.
Airways that are constructed joining from other airways will adopt the
attributes of the joined airway (such as size and wall friction factors
types).
Airways that are constructed away from other airways will adopt the default set in the Settings menu.
Left Mouse Click |
Edit the airway. Left clicking the mouse on top of an airway will show the Edit Box for that airway.
Left Mouse Drag |
Constructs a new airway from where the mouse is initially pressed, to the point where the mouse button is released.
To manually control the coordinates of the airway being constructed, select the sub-menu functions of the add button as shown below.
· Free Draw – allows the mouse to draw both ends of the airway
· Coord Exit – allows the mouse to initially draw the start of an airway, then shows a dialog box to allow the end to be entered as coordinates.
· Coord Entry – shows a dialog box to allow the start of an airway to be entered by coordinates, and then permits the mouse to complete the airway
· Coord Both – shows a dialog box to allow both the start and end of the airway to be entered by coordinates.
Place the program into Edit mode
Left Mouse Click |
Edit the airway. Left clicking the mouse on top of an airway will show the Edit Box for that airway.
Left Mouse Drag |
Selects the airways within the fence box being drawn. Selected airways can then be edited by clicking on any of the selected airways.
Hint : Selecting Multiple airways permits attributes for a large number of airways to be changed simultaneously. This can greatly speed up creating a network.
Blocks or unblocks an airway with
the highest resistance available (as defined in the Settings menu). This will
restrict nearly all airflow through the airway.
Warning: Ensure that fans or
fixed flows are not present in blocked airways, or in airways leading to or
from blocked airways. This will create a simulation error, as airflow will be
unable to travel through the blocked airway without unreasonable pressure or
heat build-up.
Deletes an airway or airways from a network
Left Mouse Click |
Delete the airway. Left clicking the mouse on top of an airway will delete the airway beneath the mouse cursor. If multiple airways have been selected, it will delete all selected airways.
Left Mouse Drag |
Selects the airways within the fence box being drawn. Selected airways can then be deleted by clicking on any of the selected airways.
Moves the selected airway, airways or airway ends to a new location
· To move an airway end (and all other attached airway ends), click on of close to the end node of an airway
· To move an airway end away from other airways, click slightly back from the airway end node. The airway should ‘break’ away from other connected airways.
· To move an entire airway (both ends), click on or close to the middle of an airway.
· Multiple airways can be moved by first selecting the airways and the dragging any one of the selected airways to the new location.
Left Mouse Click |
Opens the coordinate entry dialog box to allow the move to be specified as a coordinate or offset from the current position.
Left Mouse Drag |
Drags the airway or node to a new location in the same horizontal elevation plane. A ‘true vertical’ line is displayed showing where the move point is in relation to other airways.
Left Mouse Drag + Shift |
Drags the airway or node to a new location in the vertical plane, adjacent to the viewing screen. The Edit Plane is moved with the dragged airway to indicate where the elevation is in relation to other airways.
Copies the selected airway or airways to a different location. The original airways remain in place.
Left Mouse Click |
Opens the coordinate entry dialog box to allow the copy to be specified as a coordinate or offset from the current position.
Left Mouse Drag |
Drags the copied airways to a new location in the same horizontal elevation plane. A ‘true vertical’ line is displayed showing where the move point is in relation to other airways.
Left Mouse Drag + Shift |
Drags the copied airways to a new location in the vertical plane, adjacent to the viewing screen. The Edit Plane is moved with the dragged airway(s) to indicate where the elevation is in relation to other airways.
Reverses the direction of the selected airway. The direction of the airway, and the airflow within the airway is reversed. Fan, fixed flows and pressures are also reversed.
Inserts
a node or junction within an existing airway. The airway is split
into two airways as a result. This node can then be moved or joined into by
other airways.
Hint : Drawing an airway into the middle of another airway will automatically create a new node or junction into the joined airway.
Selects
a group of airways. Selected airways are considered ‘attached’ as
a group by a number of other Ventsim Visual™ functions such as Edit, Delete, Move or Copy, which all
treat selected airways are joined together.
Left Mouse Click |
Selects or de-selects the airway under the current mouse cursor.
Left Mouse Drag |
Fences a number of airways for multiple selection.
<Escape> |
De-selects all currently selected airways
Places
a contaminant type within an airway. A number of different
contaminant types can be chosen.
1. Contaminant
Places a standard contaminant value of one hundred (100) in an airway. Standard contaminants are considered unitless, and represent the initial concentration of a contaminant in the airway’s airflow. Downstream contaminants are diluted proportionally to this value.
2. Report Smoke
Used in the contaminant tracking routines, this will place a smoke report within an airway. After a contaminant tracking simulation, all airways below this point will be considered as contaminated. All airways upstream from this point will be considered as a potential source of the contamination.
3. Report Fresh
Again, used in the contaminant tracking routines, this will place a fresh air report within an airway. After a contaminant tracking finding simulation, all airways above this point will be considered as fresh air.
Left Mouse Click |
Places or removes one of the above types of contaminants.
Selection ManagerDisplay Options |
Shows the display options dialog box, which floats on top of the Ventsim Visual™ windows, and can be kept open at all times if desired.
Display Options control what graphics details to display, primary and secondary layers, elevations levels, saved views and copy & paste options. Because complex display can quickly become cluttered with data and information, this dialog box is useful to reduce the amount of data (and hence clutter) in the display.
Hint : The Save View function from the Saved View Menu can be used to store specific display options settings, without having to go back through the dialog box and click specific items.
Graphics |
Displays the graphics details to show in the main window. To show or hide detail, simply click the check box adjacent the item (such as nodes, or airflow arrows). To select ALL graphics, or HIDE all graphics, select the root check box adjacent Graphics.
Text |
Select the text data that is displayed on screen.
· Value displays text data associated with the data type selected in the main menu
· Airway displays the name of an airway (if set)
· Node displays the name of a node (if set)
Text data can be further limited by restricting which airways show text (from the Edit Box) and choosing Text Data > Show Limited under the View Menu
Levels |
Selects which levels (elevation ranges) are displayed on screen. To select or de-select all levels, choose the root check box adjacent to ‘Levels’.
Selects which primary layers are displayed on screen. Layers are a way to show selected airways (such as a decline system or a shaft system) on screen while hiding other airways. Primary layers can be set to individual airways in the Edit Box. To select or de-select all primary layers, choose the root check box adjacent to ‘Secondary Layer’
To make a Primary Layer Active (which results in all new airways adopting the layer name), click on the primary layer name so that it turns RED.
Figure showing Active Primary Layer set to ‘Crusher’
Secondary Layer |
Selects which secondary layers are displayed on screen. Secondary layers are similar to primary layers, and simply allow another level or layers to be displayed. Primary and Secondary Layers work in conjunction with each other, and must both be set to allow an airway with the primary and secondary layers attributes to be displayed
For example, if a particular airway is set in the Edit Box to a primary layer of ‘Decline’ and a secondary layer of ‘East Mine’ then both the Decline and ‘East Mine’ layers would need to be selected in the view manager. If either or both layer was not set, the airway would not be displayed.
To select or de-select all secondary layers, choose the root check box adjacent to ‘Secondary Layer’
Again, to make a Secondary Layer Active (which results in all new airways adopting the secondary layer name), click on the primary layer name so that it turns BLUE.
Saved Views |
Recalls views saved under the SAVED VIEW main menu. This function duplicates the functionality already found under this menu.
Copy Paste |
Selects what airway attributes are copied and paste when the copy / paste attributes function is selected under the Edit menu. The copy paste attribute function allows rapid copy of existing airway attributes on to other airways. This function duplicates the Edit Box functionality which also allows multiple airways to be selected and simultaneously changed.
Select Manager showing copy paste types
Example : An existing airway has been set as an exhaust airway with custom primary and secondary layers. To copy these attributes on to other airways,
· Select Primary, Secondary and Air Type options on the Select Box
· Select Edit > Copy Attributes
· Click the airway you wish to copy the attributes from.
· Select Edit > Paste Attributes
· Click or Fence the airways you wish to copy the attributes to.
The colour display
manager controls many of Ventsim Visual™ advanced display functions. At the
core of the manager is the ability to display any type of ventilation data as a
colour range, including the ability to hide or make transparent data outside of
a set range.
Data range of airway data, equally divided by airway
numbers. To manually change, simply enter a new value in the box. Hide or make transparent data outside of range Recalculated colour range derived from the top data
range and the range limit sliders Selectable data type to display as a colour range Transparency level slider, for data outside of data
range values Upper and lower range limiters Adjustable colours for each range. To change a colour,
click the colour square and select a new colour from palette
|
Reverse Spectrum |
Reverses the colour range direction
Restore Colours |
Restores the colours to the default Ventsim Visual™ palette.
Auto Range |
Restores the range to the full spectrum of available airway data values.
Hint: The colour manager will initially default to automatically range and set colours for the displayed data. If the range values are manually adjusted, or the colours are changed, the colour manager will no longer automatically range and adjust colours for the data displayed. To restore or recalculate the range and colours, simply click the ‘Auto Range’ or ‘Restore Colours’ buttons.
Hint: Ventsim Visual™ will store a custom colour and data value range for each type of data type. This setting is saved with the Ventsim Visual™ file.
See Colour Manager for further information.
The colour manager sub menu, accessible by clicking the arrow next to the colour manager button, contain several other functions
Show |
Shows the colour manager on screen. The colour manager will remain on top of all other windows while displayed.
Hide |
Hides the colour manager form