Thunderhead Engineering Forum

Public Forum => PyroSim => Topic started by: ab on September 18, 2015, 12:30:51 am

Title: Seems like my fire don't get hot enough
Post by: ab on September 18, 2015, 12:30:51 am
Hello Pyrosim forum!

I'm trying to make an simulation on a apartment, I want the fire to burn with 5 MW HRR and after 30 min I only get temperatures around 150 degrees Celsius (302 F) and I don't think that's correct. I have attached the FDS-file and the pyrosim-file. The window pops at around 200 seconds. Is it under ventilated or what's wrong?

Best regards

ab.
Title: Re: Seems like my fire don't get hot enough
Post by: Dave McGill on September 18, 2015, 12:46:09 pm
Hi,

The images you've shown are for a slice file 1 m above the floor, and the maximum temperature is 270 C, not 150 C. At the risk of stating the obvious, it's much hotter up near the ceiling.   :-)

If you load the other slice file of temperature (in the YZ plane) the maximum temperature at 196 s (just before the window opens) is 516 C. See below. Note that I manually set the maximum temperature range to 600 C to ensure that the problem wasn't the auto scaling of the temperature range.

Dave
Title: Re: Seems like my fire don't get hot enough
Post by: ab on September 21, 2015, 01:27:51 am
Thank you Dave!

I think the temperature is a bit low for a apartment fire anyways, I mean shouldn't the temperature after 30 minutes be higher then 150 C?

I attached three plots of my 30 min run if you wan't to take a look. I really appreciate your help!  :)
Title: Re: Seems like my fire don't get hot enough
Post by: Dave McGill on September 21, 2015, 02:22:39 pm
As shown above, the temperature exceeds 500 C, until the window opens, and the smoke layer escapes.

Put a slice flie in the YZ plane directly through the fire.

Dave
Title: Re: Seems like my fire don't get hot enough
Post by: ab on September 23, 2015, 12:18:51 am
Thanks Dave!

I'm still not sure if this result is reasonable, the temperature after the window breaks seems so low. What do you think?