Martin Griffith

Hi Andrew, you should be able to load VNETPC files in Ventsim. If it's not working, then I recommend sending us the file at ventsim.support@howden.com and we will work out what is going wrong. 

Hi Andrew, sorry you had this problem. Is it still happening? If so, I recommend reinstalling from the website and trying again. If it persists, please contact us again.

Patches | Ventsim

Hi Guido, 

Sorry you've had this problem. Please send us your file and we can work out what is going on. You can email us at ventsim.support@howden.com , or direct message me through the forum's messaging service.

Hi, 

The latest Pumpsim manual is available at this link: Official Releases | Pumpsim

This is the same link that appears in the Help menu of Pumpsim.

We are currently working on an undated PDF version of the manual whcih should be part of a forthcoming release of Pumpsim DESIGN. 

Hi Jose,

Thanks for your question. I'm not sure if you're talking about the flow into or out of the tank. There is an option to add or edit a tank discharge coefficient on the pipe connected to a tank. You can see the option on the pipe Edit Box. 

Perhaps you can send me a model and an idea of what you expect to see and we will work it out. You can post it here, or DM me the model, or also send to ventsim.support@howden.com .

A new setting has been added to Ventsim DESIGN 5.4.8.6 to allow the user to customize the minimum temperature limit.

Hi Jose, 

Pumpsim should handle this automatically. If you connect 2 tanks via a pipe, with the pressure different at both ends, you will get a flow, without a pump. 

Hi David, 

You can try adding an obstruction on the Pipe Edit Box. Or defining a different pipe type that accounts for the filling.

Is that what you mean?

Hi David, 

If you want an oval shape, I recommend using the custom profiles tool. 

In this, you set the shape, not the dimensions, of the profile, which for Oval will be a circle. Then, when you use this on an airway or a duct, you can set the width and the height to make it oval. This is in contrast to the Round shape, which only takes one input, the diameter.

Hi Joey, 

Firstly, make sure you have Bingham selected as the Viscosity Model. 

Also, make sure that you have the fluid type set on the pipes. 

Finally, check if any other properties are changing with the yield stress. In a purely gravity fed system, changing the yield stress won't change the pressure (which is set by the elevation and the fluid density) but it will change the flow rate you achieve. If is still unclear, feel free to send us the model to have a look at, or some screenshots. (ventsim.support@howden.com)

Hi Martin, 

The pressure of the blast is reduced over time, with the blast travelling over the distance of the airways of the model.

Hi, sorry for missing this post. 

I suggest checking out these other 2 threads below which deal with stench gas. 

You would use the Contaminant Simulation to simulate stench. If you fix the concentration, then this will set the concentration regardless of airflow. If you use injection, then the concentration will vary with the airlfow. This is probably what you want to do with stench, where you are injecting a set amount of gas into the airstream. I've attached a model here which demonstrates the difference. 

You can do fixed rate or log decay to model the stench dynamically. Start with fixed rate, as it is a bit more straightforward to calculate the correct rate and time than for the decay option. 

This topic has come up fairly frequently, I will make a more detailed post about it soon and reference it here. 

stenchGasCalc.vsm

For this, I suggest you email us at ventsim.support@howden.com, you will need some assistance in configuring the database. 

Hi Koray, sorry for the slow response, we have had some people away this week. You will get a further response soon from the relevant expert. 

In the meantime, if your black Ventlog data boxes have dissappeared, I would suggest looking in the Visibility Manager (the blue cog in the left toolbar) and check the Ventlog Boxes option is ticked on. Also check that you have not turned off all the text with the Text on/off toggle. 

Another colleague will respond to the second issue you raised. 

Hi Miguel, 

There is no control that will hide the linear heat sources, but leave the other preset Icons. 

What I would suggest is to use the Activity Track instead. Click the Edit cursor on the red ribbon above the airways (or go to Settings | Activity Tracks). You can add the linear heat source here instead, which won't add the icons to the airways.

Test it both ways to make sure you are getting the same answer and if you have any questions, let me know. 

There is a thread here on Activity Tracks: 

It's typically used to distribute the heat from a moving discrete heat source (like a truck) along a path, but you can also use it to apply a linear heat source and it will distribute it correctly. 

Hi Miguel, if this warning is appearing it means that the surface datum elevation above sea level and the surface datum of minegrid do not make sense with the actual coordinates of the airways in your model. 

According to the warning, the highest elevation (on the mine grid) in your model is 1437 metres, on airway with index 934. If your surface datum of mine grid setting is 4022.5m, then this would imply that the highest elevation airway in your model is at a height with reference to sea level of 1437 - 4022.5 + 237.9 = -2347.6 m? Is this what you want? If so, then it is unusual, so Ventsim is providing the warning. If it is correct, then I suggest you add another undetached airway that vertically climbs to 4022 metres on the minegrid. This will avoid the warning. 

If it is not right, then you may have misunderstood the mine grid setting, which is a common error in Ventsim. The setting Surface Datum of Mine Grid is the elevation in the model at which the surface datum condition is applied, one of those conditions being the Surface Datum Above Sea Level. To check you can go to the Info tab of the Edit Box on an airway and this will provide you with the airway elevation and the elevation with respect to sea level. 

Hi Mick, thanks for your message. 

When you run a Diesel Simulation, Ventsim is now keeping track of the use of fresh air by the diesel machines and is showing the Fresh Air Deficit warning when a diesel machine is hit by air which has been used up upstream by other machines. In this way it checking the 0.06 (m3/s)/kW requirement locally at each airway. This warning is independent of simulated DPM levels or temperatures. 

The first 2 vehicles in your road are receiving the fresh air so don't see the warning. Downstream the fresh air is used up by the upstream vehicles and the warning appears on the later vehicles. You can switch to the Diesel | Air Surplus property to see the air being used up. If a Diesel machine is placed in an airway that has negative Air Surplus, then the warning appears. 

You mentioned that the Utilisation Factor is having no effect. This is because the calculation of the fresh air usage ignores the Utilisation Factor and is based on the rated engine power of the diesel machine as, by our understanding, this is how the flow requirement is assessed. 

This is a fairly new feature and we'd be interested in any feedback or suggestions you have about it. 

Hi Xiao,

a while ago we made a change so that leakage paths are constructed even when leakage is specified as zero, meaning you can change it later.

I would say you are either using a version earlier than 5.4.1.5, or the duct you are modifying was constructed using a version earlier than 5.4.1.5. 

If you are using a version later than 5.4.1.5, then if you rebuild the duct you will be able to modify the leakage later.

You can check your version number under Help | About. 

Hi Xiao, 

After building the duct you will not be able to change the offset, to do this you need to delete the duct and build it again. 

You should be able to edit the Leakage Porosity though. First, hit escape to clear your selection, then change to the Select tool and click once on a part of the duct. The whole duct should then select. Then click the Edit tool button, this should open the Construct Duct form, which you can use to modify most of the parameters. 

Hi John,

Thanks for the message. I gave it a test and I couldn't identify the problem. If you could send a screenshot of the error that would help. 

Hi Christian, this warning means that the fan has nowhere to push the air. Airflow in Ventsim is one-dimensional, so air will only ever go in one direction in an airway. If you have the fan in a blind drift, Ventsim can't simulate that. 

Perhaps send us a picture of the error and what you are trying to do. 

Hi, 

You can usually control layers during the import process, perhaps you can send us a screenshot of the Import window that appears when you import the file into Ventsim. Or send us the file at ventsim.support@howden.com

Thanks Fred. Correct, it will only work on the visible surfaces. But they also must be surfaces and not contour lines. 

If you have contour lines, then you can convert them to a surface using Tools | Create Surface.

Hi Robin, 

The autoclose option on the fan shuts off the flow entirely. If the autoclose option is not used, then it is completely open when the fan is off. 

In your case, the off fan is adding some resistance, but not shutting off entirely.

If your simulation with the fan running is accurately predicting 30 m3/s, then in order to simulate the off fan, it would be valid for you to remove the fan and then add a resistance representing the off fan that reduces the flow to 7 m3/s.

Note, that resistance that is added through the fan definition (Tools | Fans) will still be added when the fan is off. But if you add resistance, then you may have to adjust your fan curve, which can be difficult. 

Hi Fred, 

To do this you could fix a temperature at the inlet. Make a small airway at the top of the shaft, scroll down on the Heat tab of the Edit box, under fixed data, you can set the temperature there. 

It would be a good idea to place a text box there explaining what the fixed temperatures represent.