Martin Griffith

Hi Golden, You can import .dxf and Surpac .str files into a Ventsi model. Go to File | Import and then open your file. Alternatively, you can drag and drop the file from the Windows File Explorer into the Ventsim viewer. Once you've done this, a window will come up which gives you any available import options, such as offsets or rotations or whether to split into layers. If you want to switch you the visibility of your graphical references on or off you can use the shortcut button on the left toolbar of the globe.You can open the Reference Layers tab of the Data Manager to manage the visibility and transparency of individual reference layers. You can tick them on or off and change the slider at the top to change the transparency. (see the image at the bottom of this post) As for managing the text visibility, you can do this through the Visibility Manager, which is available through the blue cog icon on the left toolbar. In here you can switch off different types of text. If you want to limit the text shown to specific airways, then I refer you to this thread which describes the Limit function:

Hi Isabela, There are a few things you can do. You can reduce the text density on the right-most slider of the Scale Manager. This will reduce the amount of airways across the whole model that are showing a text value. A more precise way to do it is with the Limit function. In the Visibility Manager (available through the button with a blue cog, switch on the Limit for Text and turn on the Limit tool with the Limit On-Off button. All the data values for your airways should disappear. To make a data value appear for an airway, open the Edit form on an airway of interest and tick on the Show Data option. Click Apply and now this airway will show a data value. You can directly select which airways you want to show a data value.

Hi, There are a few ways in Ventsim to hide parts of your model, which I will run through below. But first; if you are hiding airways in your model and you're not sure what you've made visible or invisible, or perhaps all of your model has disappeared, you can go to View | Show All, which will reset everything in your model to visible (also available in the right click menu). Also, once you've hidden something, it will be either completely invisible or transparent. You can change the transparency of hidden airways using the slider at the top of the Display Manager (highlighted red). The fastest easiest option to hide parts of the model is to go to View | Hide Zero Flows, which will hide any airways with zero air flow. How useful this is will vary from mine to mine. You can also use the Clip and Clip Level tools under the View menu. Select the tool and then drag a box over the area of interest in your model. For Clip, everything outside the box will be hidden, for Clip Level, everything outside of the levels covered by the box will be hidden. These options are also available in the right-click menu. On the Display Manager, each of the first 5 tabs gives a different method for hiding parts of the model. The Colour tab allows you to hide airways in a model according to a property's value. In the image above (highlighted in green), I've moved the bottom scale up so that the colours shown are over a range of flow quantity of 20 m3/s to 250 m3/s. Because I have also ticked the box located at the bottom of the slider, airways outside of this range (< 20m3/s) will be hidden. On the Level tab, you can select which levels of the mine are visible. A good way to focus on just one level is to click on the black light globe, which will hide all levels. Then select just the level you want to be visible. If you have no levels set up, press the green plus button to do so. There is a level wizard there as well which can help. The Air Type, Primary Layer and Secondary Layer tabs allow you 3 separate systems to organise your model. A common method is to break up the mine into Air Types of Fresh and Exhaust air. The Primary Layer system might break the mine up into designated areas and then the Secondary Layer might break it up into smaller sections again. Ultimately, it is up to the user (and the mine) how these three systems are used. If you open the Metal Mine demonstration model in VentSim (File | Load Demonstration | Metal Mine) you'll find an example with Levels, Air Types and Secondary Layers set up. If you click the blue cog on the left side of the Ventsim viewer, it will open the Visibility Manager. Here you can control the airway transparencies, as well as the visibility of the various icon types and of any text on the viewer. Finally, the Limit allows you to limit the data shown on the viewer to those airways which have the Show Data flag switched on. If you switch on the Text Limit, then to see the text for a given airway you need to open the Edit form for that airway and on the first tab, select the option for Show Data. Hope this helps, let us know if you have any questions.

Hi again Jorge, I've not been able to reproduce your problem. Perhaps try upgrading to the very latest version of Pumpsim 3.1.0.8, this may be a problem we've previously resolved. Let me know how you go. Regards, Martin

Hi Jorge, sorry you've had this problem and thank you for reporting the issue. We'll investigate this and look to fix the problem in the next update, which should be out soon. I'll report here once the new version is up. Regards, Martin

Hi, this issue has been fixed in the latest version of VentSim Design 5.2.7.8, which can be downloaded from our website. Again, thanks for bringing this to our attention.

Hi Isabela, To simulate diesel, as well as specifying the rate of diesel emission (g/kW.hr), you need to enter a diesel engine power (kW) as a point source. After that, make sure you are running the Diesel Simulation in the menu under the red Contaminant Simulation button on the toolbar, and not a different simulation type. If you still get zero CO, CO2 and DPM throughout the model, if possible please send me your model and we'd be happy to take a look. regards, Martin

Hi. When you want to zoom in on a particular part of a model, it's a good idea to put the viewer focus on that part. On the airway that you are interested in, first do a middle mouse button click. This will place the focus on the airway, meaning the airway will be included in the viewer regardless of the zoom. Hope this helps, let us know if you still have problems.

Hi, thank you for bringing this to our attention, it appears to be a bug in the software. We will fix this shortly and issue a patch release. I'll post here again once the issue has been addressed. Regards, Martin.

This issue has been resolved in Ventsim version 5.2.7.1, which is now available from the following page: https://ventsim.com/download/minor-releases/ Thank you for reporting it to us, Martin

This issue has been resolved in Ventsim version 5.2.7.1, which is now available from the following page: https://ventsim.com/download/minor-releases/ Importing fans through either the Inherit function or the Fan Import function from the Fan Database window should now work.

This issue has been resolved in Ventsim version 5.2.7.1, which is now available from the following page: https://ventsim.com/download/minor-releases/

Hi, we've fixed up one problem in relation to the paste airways function. Could you please download the latest patch (version 5.2.7.1) from the following page and check again. https://ventsim.com/download/minor-releases/ If the problem still occurs could you please tell us how many airways are disappearing? Also, to make it easier for us to isolate the problem, if possible send us the models for which you're seeing this problem, to ventsim.support@howden.com Thanks, Martin

Hi, The import function in the Fan database form is not working. We'll fix it shortly. Thank you for reporting it to us. We have been directing users to the Inherit function (File | Inherit) With the Inherit function, you can load a model and select what features you would like to inherit from it to your current model. You can select Presets | Fans to import Fans.

Hi, This is a bug with the old edit form not updating straight away. Apologies for that, we'll fix it today and post a new Ventsim patch version. I'll post here again when the new version is up. In the meantime, you'll need to deselect and reselect the airway to update.

Hi, in the later versions of VentSim, you now have the option of docking the EDIT box in the main VentSim window or have it floating as a separate window. If you dock it, then the EDIT box will remain visible even if you have no airway selected. If you want the EDIT box to disappear when you deselect airways with the ESC key then you need to have the EDIT box undocked. You can undock it by clicking and holding on the title of the EDIT box, dragging the mouse to where you want the EDIT box to be, and then releasing.

Hi, Thanks for bringing this to our attention, this is a bug that has crept in on the old edit form. We need to readjust the size of the graph to fit in the form. We'll fix this now and release a VentSim patch version. I'll post again here when the new version is up.

In Ventsim 5.2, we've included some more Goal Seek! targets and adjusters. Added to the list of adjusters are Fixed Flows and Pressures, as well as Rock Wetness Fraction. Rock Wetness Fraction is often a tricky parameter to obtain, or calibrate. If you have a temperature target you are aiming for you can now use the Goal Seek! to find the needed Rock Wetness Fraction. You can do this for a single airway, or select multiple airways and adjust them together. If you prefer you can select the whole mine and adjust the Wetness Fraction globally. If you do this, the Goal Seek! will scale the existing wetness fraction, rather than set the same wetness fraction throughout, meaning any existing differences of wetness fraction in your mine will also be scaled. In the target list, as well as including Air Velocity, we've added a list of common gases that might be simulated in a mine. This means that you could, for example, adjust a fan speed or a fixed flow in order to achieve the required dilution of a given gas to an acceptable level. If there's anything else you feel would be useful to include in the Goal Seek!, such as another gas, please let us know.

Hi Bruno, To simulate the use of a mercaptan gas, or a stench gas, in Ventsim, there are a few options. The easiest way is to use the Contaminant Simulation. Starting on the Contaminant tab of the Edit Box, add a contaminant concentration to an airway from where you will release the stench gas. Then run a Contaminant Simulation. Ventsim will switch the airway colors to "Contaminants | Spead Mix" which will show all of the areas of the mine where the released contaminant will reach and the concentration. However, this simulation assumes an infinite amount of time. It may take a very long time for the stench gas to reach parts of the mine, which could be important to your emergency plan. To see how much time it takes for the gas to reach each airway, switch the color and text data to "Contaminants | Spread Time". Another factor to consider is the release rate and duration of your stench gas, because of the emptying of the stench gas cylinder. To analyse this effect, you need to run a Dynamic Contaminant Simulation. This will simulate the variation with time of the stench gas movement in the mine (remember, before running a dynamic simulation, place Dynamic Monitors in airways of interest). On the Contaminant Tab of the Edit Box you can experiment with the stench gas release. With Fixed Rate, you can stop the gas release after a set amount of time. With Linear and Logarithmic Decay, you can stop the release after a set amount of time, but also have the release rate decay over time. A stench gas release set to end after a set amount of time with a logarithmic decay can model a gas cylinder releasing gas, with the cylinder pressure dropping, and therefore the release rate falling too. In this way you can examine how long it takes for the stench gas to reach a particular airway and if it will arrive with sufficient concentration to be detected. Hope this helps, please let us know if you have any other questions.

New to VentSim DESIGN 5.2 is Piston Effect Modeling. When, say, a truck drives along a tunnel, it will create a blockage to the airflow. But due to the velocity of the truck, it will also create a pressure as it pushes the air in front of it, like a piston, much like the approach of an underground train can be detected on a train platform by the increased airflow. How great this piston effect pressure is will depend on the relative velocity between the air and vehicle, the frontal area of the vehicle, the cross-sectional area of the tunnel and the vehicle’s shape factor, or coefficient of drag. To model this in VentSim, a vehicle can be added to an Activity Track. First, define an Activity Track. In the example here, I’ve selected the decline of the mine, and then gone to Settings | Activity Tracks. In the Activity Track form, I’ve renamed the track “Truck Path”, clicked on Add Selection (to add the selected airways to the track) and checked on “Piston Effect” and “Bi-directional”, so Ventsim will simulate the piston effect and model the vehicles as going up and down the decline. However, the piston effect won’t be calculated until I’ve selected a Vehicle Type. In this example I’ve selected Haul Truck for Vehicle Type; this type contains information on the truck shape, speed and area. The Vehicle Type can be edited in the Presets form, where you’ll also find data for small trucks, cars, hoist cages and falling rock. I’ve also added a Heat Type, “Truck AD55” which contains information on how much heat the truck produces. This is not needed for the piston effect calculation, but may be required for any Heat or Diesel Simulations I do. I’ve made Units equal to 2, to represent 2 trucks using the path. A green ribbon should have appeared over the airways representing the Activity Track. If I like, I can add other vehicle and heat types to the track. To get back to the Activity Track Editor later, I can find it under Tools. Alternatively, I can click with the Edit Tool directly on the track ribbon in the viewer. A double-click with the Zoom Tool will do the same thing. If I want to know which airways currently belong to my track I can click on the option to “Highlight in 3D view” which will highlight my track. Now when I run the Air Simulation, Ventsim will calculate a Piston Effect from these 2 trucks. Now, the Air Simulation is a steady-state solver, meaning it will average out dynamic effects, such as moving trucks. To do this, Ventsim calculates the fraction of time each truck spends in each airway, relative to the total time taken to complete a traverse of the whole track. In the steady-state Air Simulation, this fraction of the piston effect pressure is applied to the airway. When a vehicle is acting on a path, arrows will appear on the ribbon indicating the direction of the vehicle action. In this case, I selected “Bi-directional”, so I have arrows pointing both ways on the track ribbon. The amount of pressure applied can be seen through the colour and text data; Pressure | Pressure Piston Effect gives the total added pressure from the piston effect in each airway, while Pressure | Pressure Piston Effect / Lgth gives the same, but per unit length of each airway. The amount of piston pressure will vary with the airway velocity, area and direction, and with the vehicle speed, frontal area and drag coefficient. There are several other options in the Activity Track Editor. “Change Track Direction” will begin the track from a different end of the track. “Enter vehicles per unit length” will allow me to specify an amount of traffic in units per meter, rather than units per track. “Delay restart” will create a pause between when a vehicle finishes its traverse of the path and when it begins again; this can be used to represent a vehicle using a path intermittingly, or perhaps parking for some time. For a Dynamic Simulation, there is the potential to model the piston effect dynamically. In the Activity Track Editor, units can be selected to be modelled “discretely” or “as distributed effect”. The second option is the default, and it will basically model the piston effect (and any heat or diesel effects) in the same way as in the Air Simulation, distributing the effect along the track. If the “discretely” option is chosen, then the position of the vehicle is modelled and updated throughout the Dynamic Simulation and the entire effect of the piston (and any heat or diesel) is applied at the airway where the vehicle is located at that instant. In this way, the dynamic effect of the vehicle unit can be modelled. This feature adds a new level of dynamism to Dynamic Air, Heat and Diesel Simulations, allowing the user to track the effect of vehicles through time. However, a word of warning: enabling this feature will most likely require a much higher level of spatial and temporal resolution than is usually required in your model; that is, you may have to reduce Settings | Dynamic | Dynamic Increment, and increase Settings |Dynamic | Maximum Subcells. These settings will have a strong effect on the results of any vehicles modelled discretely; as a side effect, they will significantly slow the speed of your Dynamic Simulation. You will need to experiment with this feature; don’t hesitate to contact us at support if you have any questions on this. When using the Piston Effect, you may see this warning: Basically, the piston effect can only be modelled on contiguous Activity Tracks. If there are tracks with airways included which aren’t connected to other airways in the track, then Ventsim cannot determine the path along the track, so the simulation will fail. If this happens, open the Activity Track Editor and go to the track indicated by the warning. You will either have to remove or connect any unconnected airways, or turn off the track features, such as piston effect, that require a determination of the path. Please let us know how you go with the new Activity Track features and the Piston Effect, and contact us if you have any questions. This is a very new feature to Ventsim DESIGN and we are actively seeking to get your feedback and refine it for improved future use.

Hi Shane. Fixed Flows as Source settings and Velocity as a Goal, we can add those in an update soon. To add things like gas levels as Goals, we would need to bring the Gas Simulation into the Goal Seek!, which is possible, but would need a a fair bit more work. I'll add it to the list of potential future enhancements and keep you posted. Thanks for the feedback and suggestions!

New in Ventsim 5 is the Goal Seek. The Goal Seek calculates a setting for you (such as a Fan Speed, a Resistance, a Regulator Opening or heating or cooling input) on one or more airways, so that you achieve a particular variable output (airflow quantity, pressure, temperature) on another target airway. This allows you to, for example, determine a fan speed on an intake fan which would give a particular flow rate in a different part of the mine. Rather than using trial and error back and forth to find the correct fan speed, the Goal Seek! will do it quick smart. It does so by running multiple Air and/or Heat Simulations to calculate the correct setting, using a fast numerical algorithm to minimize the time needed to calculate. The Goal Seek can be found under Tools -> Goal Seek Once you've opened the Goal Seek!, you need to select the airways to adjust, or the Source airways. You can choose to adjust: Resistance Fan Speed Sensible Heat Latent Heat Refrigeration Regulator Opening Orifice For the fan and regulator options you are limited to airways which already have a fan or regulator. If you select more than one airway, then the parameters will be adjusted equally on all airways by a common factor. For the goal, you are limited to one airway and you can target: Quantity Total Relative Pressure Dry Bulb Temperature Wet Bulb Temperature To select a target airway, press the select button in the Goal panel and then select a target airway. The Goal data will update with the current value for that airway; you can adjust the target up or down. When you're ready, press Goal Seek! and the solution algorithm will begin. The progress of the Goal Seek will update in the graph. The target is shown by the blue line. The red line shows the progress of the target airway value towards the target and the green line shows the change in the source airway parameter. The Goal Seek will continue until the target airway is within a small tolerance of the target. Goal Seeking tasks which involve temperatures or heating or cooling will tend to take longer, because the Heat Simulation will be running as well. If the Goal Seek! was successful and you're happy with the result and want to keep it, close the Goal Seek and you will prompted whether you want to copy the result to your model (you can Undo any changes after closing). Often your Goal Seek! will fail and you'll get a message telling you that the goal seeker is not converging. There are a number of reasons this can happen: your target value is not functionally-related to the adjusters. This means that changes to the adjustment parameters do not have a significant effect on the target value. This can happen if you are adjusting a fan speed, but your target airway is in a part of the mine that is not affected by that fan, so when you change the fan setting, nothing changes in the target airway. the target value is unachievable. This means that the limitations on the adjustment parameters and the nature of the mine system is such that you can not reach the target. This can happen if you are seeking to reduce a resistance to achieve an increased airflow in the target airway. You can not reduce an airway resistance to or beyond zero, so there is a natural limit to the maximum airflow achievable, for a given supplied pressure. if you have Natural Ventilation Pressure switched on, then in some mine models, there can be a natural variation in temperature and airflow, indicative of a mine with no steady-state solution of air and heat. In such cases, for Goal Seek! attempts where you have chosen temperature related adjusters or target, and have Natural Ventilation Pressures on, then the Goal Seek can sometimes struggle to converge. Where the Goal Seek! fails, it will revert to the original state and you can adjust your input parameters and try again. If you have any questions about the Goal Seek!, any suggestions, or any feedback from your own experiences with it, please let us know in this thread.