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Messages - Jared

Pages: [1] 2 3 4
1
PyroSim / Re: Ramping up time Custom
« on: September 26, 2017, 08:53:21 am »
It depends entirely on what you are attempting to model.  I'd recommend looking into a "t-squared" fire in the SFPE Handbook and the NFPA Handbook.  Remember to read about the required knowledge base for running a FDS fire model as well.

2
PyroSim / Re: STOP: Numerical Instability
« on: September 17, 2017, 03:54:51 pm »
This error occurs for a number of different reasons but basically means that the time that it took to complete each time step was too long and getting more out of control.  When this error happens, open up smokeview and load a plot3d file which is created by the numerical instability at the last time step of the simulation before the crash.  This should help you determine what went wrong so that you can adjust the model accordingly.

3
You will likely get better response if you post this type of FDS specific issue to the FDS discussion forum.  https://groups.google.com/forum/#!forum/fds-smv

4
You could input a fan with an area equivalent to the area of the fan with the known volume of air movement.. this won't be perfect but it should be close.

5
PyroSim / Re: Rubber material
« on: May 29, 2017, 02:00:32 pm »
Check the SFPE Handbook, Ignition Handbook, etc.  Finding these values is sometimes hard and it often times may not be exactly the same material that you are intending to use in your project.  The best way, albeit expensive, is to send a sample of your material off for testing to experimentally determine your material's flame characteristics.

6
PyroSim / Re: FDS6 error
« on: May 29, 2017, 01:57:06 pm »
That picture is hard to tell, but I believe that is your HVAC node/duct that is showing up.  You would have to repeat that process for the rest of the nodes/ducts.  Without you posting the entire code, it is hard to diagnose what is going wrong.

7
PyroSim / Re: FDS6 error
« on: May 28, 2017, 08:28:38 am »
Post your entire code please.

8
http://www.engineeringtoolbox.com/equivalent-diameter-d_443.html

9
PyroSim / Re: Jet Fan Orientation
« on: May 11, 2017, 05:43:24 pm »
From the Pyrosim Manual:

HVAC Vents
HVAC Vents are used to represent the junction between the HVAC system and the rest of the
computational model. See Chapter 8 for more information on using vents. To define an HVAC Vent:
1. On the Model menu, click New Vent.
2. In the Surface box, select HVAC.
3. Click the Geometry tab. Specify the appropriate 2D geometry of the vent.
4. Click the HVAC Properties tab. If you want the flow from the vent to go in a direction not
perpendicular to the vent, click Louver. Specify the values X, Y, and Z as a vector of the direction
you would like the flow to be directed.
5. Click OK.

10
Pathfinder / Re: Evacuation strategies in an airport termina
« on: May 05, 2017, 07:02:13 am »
You can make small rooms without doors if that is your intent.  Or you can slow your occupants travel speed down with some justification for what value you picked.

11
PyroSim / Re: Pyrosim issue
« on: April 28, 2017, 08:17:15 pm »
Add a &REAC line to your model.  Look at the user manual and search for &REAC.  Currently you are telling the model that "X" is going to burn but you aren't saying what the properties of the burn will be.  That is what the &REAC line will do.

12
PyroSim / Re: Pyrosim issue
« on: April 26, 2017, 10:40:56 pm »
This error is referring to a vent improperly setup within Mesh 1.  So the issue is with the vent, not the mesh.  Ensure that your vent is on the plane of the mesh that you created and this error should be solved.

13
PyroSim / Re: flashover fire
« on: April 06, 2017, 07:07:00 pm »
I want to initially caution you on what you are going to use the results of this fire model for.  While fire spread is possible to model in FDS, it is mostly unvalidated due partially to the incredible amount of variables which affect spread.  One of the materials you have picked even has a "CAUTION" note due to its missing validation in the "FYI" field.

Without seeing the results or layout of the model it is tough to understand exactly what is going wrong or what you expect to happen in the model. 

14
Pathfinder / Re: staircase and occupant issues.
« on: March 31, 2017, 08:28:03 pm »
It is not really clear from your pictures what the issue is.  What mode are you running the model in?  SFPE or Steering?

15
PyroSim / Re: Problem with instability
« on: February 19, 2017, 11:06:34 am »
100MW is a huge fire and the geometry which you described is also very big.  Without seeing the code it is tough to determine what may be causing numerical instability.  When numerical instability happens it will automatically create a plot3d output on the last timestep that FDS performed.  If you load this plot3d file in smokeview, it may help show where the actual issue is taking place (sudden increase in value at a specific point).  If that is no help, slowly start to remove features from your model until you can run without numerical instability.  Then add the different features back in without the one that caused the issue.  This is a time extensive fix however.

What is your ramp time of your fire?  Do you have forced ventilation?  How large are your meshes?

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