Other Species like HCN

[Michael]

Is it possible to simulate with other species like HCN or HCL in the
REAC-line? Which inputs must be given in this case (Yield?) Can the
concentraions be shown in output files or in smokeview?

[Jianping]

I don't think it is possible yet with the present version of FDS. you
may have two options by modifying the source code:

1) The simple one is to modify the state relationship by adding extra
species as done for CO and soot;
2) The more complex one is to solve an extra conservation equation for
the species you are interested in using the flow field calculated by
FDS.

If all done properly, you should then be able to view it in smokeview.

[Kevin]

See the User's Guide chapter on Combustion, and read about the
specification of OTHER on the REAC line to represent components of the
fuel that are not C, O, N, or H.

[dr_jfloyd]

See the U guide for the REAC line. there is an "other" species you
can define.

[Bart Van Weyenberge]

Hi,

I see these are old posts but is it by now possible to enter an HCN-yield in the same way as you enter an CO-yield (in fds5 or 6)?

The purpose is to obtain slice files.

Thanks,

Bart

[Craig Weinschenk]

If you want to use a species like HCN in the products you will have the define the lumped product species with the desired HCN yield. Only soot and CO have yield parameters as part of simple chemistry.

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Craig Weinschenk

Fire Research Division

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www.cweinschenk.com

[info]

Hi,

I see in EVAC 2.5.0 User Guide that the FED is calculated taking into account not only CO, CO2 and O2, but also HCN, NOx and irritants.

But, if I just specify a fuel in REAC line, are these substances included? 

Or should I define the yield of these substances? 

Thanks

[dr_jfloyd]

If you wish to include product species other than CO2, CO, and H2O, you will need to define those species with SPEC lines and define the complete chemical reaction on REAC. See the example in the 12.2.1 of the guide.

[info]

Hello Jason, the example is very useful, thanks.

But, should I define CO_YIELD and SOOT_YIELD in this example?

thanks

Il giorno mercoledì 2 aprile 2008 13:56:45 UTC+2, Michael ha scritto:

[dr_jfloyd]

Follow the example. The example does not CO_YIELD or SOOT_YIELD.

[info]

Yes. But the User Guide says: "SFPE Handbook is used to find soot and CO yields for PVC".

In which way do these quantity affect the example?

Il giorno mercoledì 2 aprile 2008 13:56:45 UTC+2, Michael ha scritto:

[dr_jfloyd]

To use HCl you must explicitly define the chemical reaction (e.g. eq 12.7). Per the example we get the formula of PVC (C2H3Cl) from the handbook along with a soot and CO yield of 0.172 and 0.063.

So to determine the inputs for FDS we need to balance the reaction:

C2H3CL + air -> products where

air = x O2 + x 3.76 N2

products = a HCl + b H2O + c CO + d CO2 + e C + x 3.76 N2

you use the definition of the yield to determine b and e, the assumption at all Cl goes to HCl to get a. b,d, and x are then determined to balance the stoichiometry.

with x,a,b,c,d, and e know, you can then define the lumped species for AIR and PRODUCTS and with those definitions define the NUs on the REAC line.

[info]

Ok, now it is clear to me.

Thank you Jason!

Il giorno mercoledì 2 aprile 2008 13:56:45 UTC+2, Michael ha scritto: