Well ventilated fire, CO Yield and CO output slice
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Guillem
Jan 25, 2012, 6:15:23 AM1/25/12
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Good mornig,
I'm working in a fire simulation, in a well ventilated fire scenario.
I have read in the manual, and asked in this forum how to obtain the
slice file from CO, in order to compare the results with the NFPA
parameters along the simulation time. For the moment i put a CO_YIELD
in the reac line, and create a slice file:
QUANTITY='VOLUME FRACTION', SPEC_ID='carbon monoxide'
I though this was a good method, but the CO seemed a little low,
maximum 150 ppm near of fire, i don't know if it's normal.
Well, i read in the table 14.1 of user's guide and the anotations
below (pag 167-168), that i can't use this method using the mixture
fraction model, that we use.
So, how can i know the volume fraction of CO if i use the mixture
fraction model?
I'm working in a fire simulation, in a well ventilated fire scenario.
I have read in the manual, and asked in this forum how to obtain the
slice file from CO, in order to compare the results with the NFPA
parameters along the simulation time. For the moment i put a CO_YIELD
in the reac line, and create a slice file:
QUANTITY='VOLUME FRACTION', SPEC_ID='carbon monoxide'
I though this was a good method, but the CO seemed a little low,
maximum 150 ppm near of fire, i don't know if it's normal.
Well, i read in the table 14.1 of user's guide and the anotations
below (pag 167-168), that i can't use this method using the mixture
fraction model, that we use.
So, how can i know the volume fraction of CO if i use the mixture
fraction model?
Chris
Jan 25, 2012, 7:23:33 AM1/25/12
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If you have no real test to compare with, how do you know that the
obtained value is too low?
obtained value is too low?
Guillem
Jan 25, 2012, 7:38:45 AM1/25/12
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Hi Chris, i don't know it for sure, of course, but it's strange that
NFPA talk about this maximum contents:
Maximum of 2000 ppm for a few seconds
Averaging 1150 ppm or less for the first 6 minutes
Averaging 450 ppm or less for the first 15 minutes of the exposure
And i watch just above of fire, 150 ppm.
NFPA talk about this maximum contents:
Maximum of 2000 ppm for a few seconds
Averaging 1150 ppm or less for the first 6 minutes
Averaging 450 ppm or less for the first 15 minutes of the exposure
And i watch just above of fire, 150 ppm.
Chris
Jan 25, 2012, 8:08:32 AM1/25/12
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These are tenability criterias. How much CO you really generate
depends mainly on your fire-size and your ventilation.
> > > fraction model?- Zitierten Text ausblenden -
>
> - Zitierten Text anzeigen -
depends mainly on your fire-size and your ventilation.
>
> - Zitierten Text anzeigen -
Guillem
Jan 26, 2012, 5:49:46 AM1/26/12
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Ok, but my main question was, can i use a slice file from volume
fraction with the mixture fraction model?
If it's not possible, how you get this output?
Regards,
Guillem
fraction with the mixture fraction model?
If it's not possible, how you get this output?
Regards,
Guillem
dr_jfloyd
Jan 26, 2012, 8:13:20 AM1/26/12
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The quickest way to answer these kinds of questions is to try, the answer is yes. The outputs for species are not tied to the combustion model; they only require that the species be present in the computation (so you will get an error if you were to ask for a slice of helium and your input didn't contain the species helium).
Guillem
Jan 27, 2012, 4:10:58 AM1/27/12
to FDS and Smokeview Discussions
Ok, clear.
I did some tests, but didn't know if the results were good.
Thanks.
I did some tests, but didn't know if the results were good.
Thanks.
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