Thunderhead Engineering Forum

Please login or register.

Login with username, password and session length
Advanced search  


Forum moved to

Pages: 1 2 [3] 4 5 ... 10
 on: July 26, 2019, 02:11:57 pm 
Started by briancohan - Last post by briancohan
1. Show occupant counts in groups like Pyrosim shows cells in a mesh.

I know I can select an occupant group and it will tell me how many occupants are within that group, but I would like to be able to quickly glance to make sure occupant loading on each floor is what I expect it to be. I tend to group occupants into floors and then rooms/areas. If the numbers were presented right there, it would make comparing to occupancy calcs much simpler.

2. Allow rooms to be grouped aside from just what floor they are located in.

I do like how rooms are sorted into their respective floors. However, I would also like to be able to group items into groups that are not dependent on floors. For example, I would like to create a group for each stairwell. If I need to update the width for all the stair elements in a given stairwell, it would be nice to have them all under one group rather than having to go by each floor.

3. Add a visual indicator on the Run Simulation dialog box to indicate that the simulation is running or complete.

Sometimes, I do not want the results to show when the simulation is finished. I have the check box deselected. Due to this, I would often fail to realize that the simulation had completed running for a few minutes. It would be useful if there was a visual (or audible) cue that would catch your attention once complete. I'd suggest a faint yellow or gray square while the simulation is running, and then replace it with a bright green circle once the simulation is completed.

4. Negate conflicts with disabled occupants.

If I want to change the occupant loading for a moment to see how it would affect the results, I would disable a group of occupants and then add new ones (which could be deleted later). I noticed in a crowded assembly space that I had a lot of errors due to enabled occupants clashing with disabled occupants.

 on: July 24, 2019, 04:07:19 am 
Started by rigal357 - Last post by mr_paul
Hello rigal357,

You can right-click the mesh and select 'open mesh boundaries'. I think this is what you are looking for.

 on: July 23, 2019, 05:35:15 am 
Started by Niklas - Last post by Niklas

How to locate HRRPUL in pyrosim. I am always getting error when I try to model.

 on: July 23, 2019, 04:02:35 am 
Started by Stefan Löffel - Last post by Stefan Löffel
Hello everyone

I am new to FDS/PyroSim modelling and I am attempting to model fire suppression of post-flashover compartment fires. The goal is to produce numerical models which replicate full-scale experiments conducted a while ago. I have successfully modeled the fire development and am now looking at the suppression phase.

For my current model I have a 2.4 x 3.6 x 2.4m compartment in which I placed a burner with a specified HRRPUA of 601.4 kW/m2. The fuel that I am using is pine with an auto-ignition temperature of 427 degrees. I have implemented a single nozzle which is set to activate once an average ceiling temperature of 840 degrees has been recorded. I understand that it is possible to suppress burner fires using the extinguishing coefficient However I have simulated various scenarios where the extinguishing coefficient ranges from 16-250. Furthermore, the flow rate of the nozzle is set to 300LPM for an infinite duration, however, the temperature only decreases to approximately 700 degrees before reaching a plateau which is also indicated by the HRR which remains at 3850 kW throughout the simulation which does not correlate with the experiment in which a flow of 115LPM was used for a duration of 45 seconds to fully extinguish the fire.

This makes me think that either I am misinterpreting:
  • The Reaction. Under the "Edit Reactions" tab I enabled fire suppression and have set the autoignition temperature equal to 427 degrees (autoignition temperature of the pine). However, I have read up about the critical flame temperature in the FDS manual and am uncertain as to whether or not I should leave it at the default value of 1427 degrees
  • The Burner.
As i mentioned I set the HRRPUA to 601.4 kW/m2. The reaction is governed by the reaction properties assigned to the fuel i.e. pine. Since the pine has an autoignition temperature of 427 degrees it is first necessary for the burner to heat up to that value before a reaction takes place or not? Therefore do I need to adjusted the thermal boundary condition under the thermal tab of the burner to a fixed temperature with lets say a surface temp of 650 degrees to ensure that the reaction takes place or should I keep it at ambient temperature and use an ignitor to initiate the reaction? I think this may be my issue.

I understand that the explanation of my issue may be confusing but like I said I am new to FDS/PyroSim modelling. I have attached the psm.file to make things clearer.

Thank you in advance.

 on: July 19, 2019, 03:00:57 pm 
Started by faker - Last post by Bryan Klein
Many people write scripts to run a collection of FDS files from the command line.
Thunderhead does not provide support for this use case, but it's not uncommon to run simulations this way.

Here is a basic example from

if you are running on windows then create a file named runcases.bat (using the .bat extension is the key).

Put in this file:

fds case1.fds
fds case2.fds
fds casen.fds

To run this "batch" file type runcases at a command line.

You would need to add the path to fds.exe (bundled with PyroSim) into your system environment variables.
For the default installation, the path to fds.exe is "C:\Program Files\PyroSim 2019\fds".

 on: July 19, 2019, 02:37:45 pm 
Started by KR - Last post by Bryan Klein

It's difficult to understand the problem from your post here.
Please email your Pathfinder file to


 on: July 19, 2019, 03:27:33 am 
Started by KR - Last post by KR
Dose anybody have problem with new version like me?

I've started to made new model since Monday to now but it always struck.

What happend with Pathfinder program??

If anyone have suggestion,please help me :'(

 on: July 18, 2019, 01:43:41 am 
Started by Helene - Last post by Zodiass
I think it works great.

 on: July 16, 2019, 04:52:25 am 
Started by faker - Last post by faker
I have created many FDS models that I want to compute with pyrosim, but manual operations are not very convenient. I want to use "BAT" to write a program to execute them continuously. I don't know if you have any experience in this area. Thank you.

 on: July 15, 2019, 09:27:42 am 
Started by Bryan Klein - Last post by Bryan Klein
This topic has been moved to PyroSim.

Pages: 1 2 [3] 4 5 ... 10