Volumes with different temperatures

[buha]

Hello!

I want to model a fire in a building where the interior air temperature is 20 *C and the exterior air temperature is -20 *C. The windows and the doors of the building will be opened.

It is possible to define volumes with different temperatures in FDS?

Thank you!

[Randy McDermott]

FDS User Guide Sec. 6.5

&MISC TMPA=-20/

&INIT XB=..., TEMPERATURE=20./

--
You received this message because you are subscribed to the Google Groups "FDS and Smokeview Discussions" group.
To unsubscribe from this group and stop receiving emails from it, send an email to fds-smv+u...@googlegroups.com.
To post to this group, send email to fds...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/fds-smv/87f5e44e-e69d-4bad-af7f-c9f320571a70%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Randy McDermott]

p.s. I'll be interested to see what a -20 C TMPA breaks.  I would also go ahead and set on MISC HUMIDITY=0.

[Dave McGill]

Randy,

I've used that temperature differential without a problem.

Dave

To view this discussion on the web visit https://groups.google.com/d/msgid/fds-smv/CAC6wax17%2Bf1iZVvMtQqbe%2BZ-3x6jHN-26xquY1pMEGrhsG0f6Q%40mail.gmail.com.

[buha]

Thanks for the suggestion, Randy!

I made a test but I'm not satisfied with the results.

I want to start a fire in a building (were the ambiental temperature is 20 C) and see the outside temperature influence on fire development.

If I use &INIT to define a volume with -20 C for the exterior air, this volume with air will soon be heated up. In reality the outside temperature is almost constant and in the building cold fresh air is introduced.

I would like to use the open mesh boundaries to better capture the spread of smoke outside of the windows.

[Gregor]

can you attach your temperature curve?

[Dave McGill]

Buha,

I will work if you make the ambient temperature -20 C, and use &INIT to set the internal temperature to +20 C.

Dave

To view this discussion on the web visit https://groups.google.com/d/msgid/fds-smv/53869ce5-7801-4724-8087-025b8589203d%40googlegroups.com.

[Randy McDermott]

I wrote to use -20 C as TMPA and use INIT T=20 for the interior.  I cannot imagine what you are doing nor why you are not satisfied with the results.

On Fri, Sep 5, 2014 at 8:44 AM, buha <zeno.g...@gmail.com> wrote:

To view this discussion on the web visit https://groups.google.com/d/msgid/fds-smv/53869ce5-7801-4724-8087-025b8589203d%40googlegroups.com.

[buha]

Sorry for my English, I misread your answer and the User Guide.

Initially I thought it was a typo (&MISC TMPA=-20/  &INIT XB=..., TEMPERATURE=20./ instead of &MISC TMPA=20/  &INIT XB=..., TEMPERATURE=-20./) but reading Dave answer I understand how to approach the problem.

Thank you very much!!