Thunderhead Engineering Forum

Please login or register.

Login with username, password and session length
Advanced search  


Forum moved to

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - jharbold

Pages: [1] 2
PyroSim / Re: Pyrosim burner
« on: May 16, 2019, 10:00:59 am »
How big is your burner going to be?

HRRPUA = HRR per unit area

HRRPUA = 2500 kW / area of the burner

PyroSim / Re: massless tracer for new gas species
« on: May 06, 2019, 08:01:18 am »
Read chapter 18 of the FDS user guide.

PyroSim / Re: The smoke doesnt go up to the roof after simulation
« on: April 29, 2019, 06:31:02 am »
At the least, you are going to need to post your file in .psm or .fds format.  It seems that there is an issue with the geometry of your model, but it is impossible to tell from commentary alone.

PyroSim / Re: Sprinkler-controlled fire
« on: April 25, 2019, 10:31:43 am »
To respond to this and the previous question, you ultimately need to make these decisions based on appropriate engineering judgement while clearly stating the assumptions and limitations of your modeling technique and approach.

What is the purpose of this model?

PyroSim / Re: Sprinkler-controlled fire
« on: April 24, 2019, 10:34:31 am »
There are several different approaches based on what you are trying to prove and what assumptions you are willing to make.

One way is to simply add sprinklers into the model and let them actuate and flow water.  However, you should research the possible shortcomings of this approach based on the ability of the sprinkler water droplets to penetrate the plume within FDS and also how FDS produces a fire.

Another approach is to run a model with sprinkler heads without water, note the time in which the sprinklers activate, and from that point forward make the assumption that the HRR remains constant at that value (terminates growth) for the remainder of the simulation.  This can be a very conservative approach depending on the fire you are attempting to model.

PyroSim / Re: Pyrosim query
« on: April 23, 2019, 07:47:00 am »
You can view the .fds script at any time by clicking the "Record View" tab at the bottom of the screen.

PyroSim / Re: Radially spreading circle instead of ring
« on: April 11, 2019, 10:00:33 am »
Are you sure that your fire is properly ventilated?  Are flames shown at the boundary of the simulation?

PyroSim / Re: Cannot show result in Pyrosim 2018
« on: November 21, 2018, 03:53:39 pm »
Try going into the output file folder and clicking the .smv file to open it.  If your computers asks which program to use, search for "smokeview".

PyroSim / Re: Can I defy a new surface by myself?
« on: September 08, 2018, 08:45:10 am »
Perhaps look into justifying the use of a straight tunnel as opposed to incorporating the use of a non-straight model.

PyroSim / Re: Hiding geometry in 'pyrosim results'
« on: August 03, 2018, 02:31:59 pm »
On the left sidebar it says "PyroSim Geometry" in bold to indicate that this is selected to be viewed.  If you double click that then the block will go away completely.  Is that what you want?

Pathfinder / Re: waiting time - queue lengths
« on: July 24, 2018, 02:57:20 pm »
There may be a more built-in way, but why not take the raw data from each person and use that to determine the time values that you are looking for?

PyroSim / Re: FDS notepad file into pyrosim file
« on: June 29, 2018, 08:38:10 am »
Pyrosim reads .fds files.  Just open your normal notepad file.  Make sure that when you are in notepad, you are saving your file as .fds as opposed to .txt.

PyroSim / Re: FDS Parallel
« on: June 29, 2018, 08:33:43 am »
You are going to have better luck researching this in the FDS forum!forum/fds-smv.  My basic understanding is that you should only set as many meshes as you have REAL cores, as opposed to logical cores (12 meshes).

PyroSim / Re: How to model jet fan in Pyrosim 2012
« on: June 15, 2018, 02:53:48 pm »

If this tutorial is too advanced, start here ( and learn what you don't understand.

PyroSim / Re: IGNITION D*
« on: June 15, 2018, 02:51:34 pm »
I don't follow.  Surface temperature is not used in this equation - Q dot is.  Further, there is a calculator at the bottom of the page.

Don't get hung up on what the perfect D* value is.  Perform a mesh sensitivity analysis to determine if your mesh size is appropriate.  If you do not know what a mesh sensitivity analysis is, I would recommend that you carefully read the Disclaimer of the FDS user guide and reconsider your use of FDS.

Pages: [1] 2