Problems creating gasoline reaction

[max3...@googlemail.com]

Hi guys,

I am new to the forum. I am currently working on a FDS project for uni in which I want to simulate a gasoline fire. 

Since gasoline is not part of the provided fds library I gathered some data to create the reaction myself. To ensure that my model is working I tested it with 

a polyurethane reaction which is working fine. But somehow my gasoline reaction is not working and I am not sure why is that. My reaction is listed below:

&REAC ID='Gasoline (Isooctane)', FUEL='REAC_FUEL', FORMULA='C8H18', CRITICAL_FLAME_TEMPERATURE=2104.0, AUTO_IGNITION_TEMPERATURE=246.0, HRRPUA_SHEET=2400.0, HRRPUV_AVERAGE=3000.0, CO_YIELD=0.01, SOOT_YIELD=0.037, HEAT_OF_COMBUSTION=4.46E4, IDEAL=.TRUE./

Am I missing something? Thanks in advance for the help.

Max

[dr_jfloyd]

Why are you changing the default values for HRRPUA_SHEET and HRRPUV_AVERAGE?  What is you basis for doing this?  

If you are saying your fuel is octane and that you have measured the H_O_C to be 44600 kJ/kg with a 0.01 CO yield and a 0.037 soot yield, why not just do:

&REAC FUEL='N-OCTANE',CO_YIELD=0.01,SOOT_YIELD=0.037,HEAT_OF_COMBUSTION=4.46E4, IDEAL=.TRUE./

[max3...@googlemail.com]

Thanks dr_jfloyd,

it worked as you described! Can you tell me what I did wrong?

[dr_jfloyd]

By default, the simple chemistry combusiton model assumes mixed is burned as long as the extinction criteria is avoided.  By setting AUTO_IGNITION_TEMPERATURE=246.0, you are telling FDS to not allow any combustion unless the local temperature exceeds 246 C.  Unless you had engineered some form if ignitor in your input file, temperatures would start at ambient which would mean no combusiton. I am guessing this was probably your error.

[max3...@googlemail.com]

Okay I see what I did wrong thank you! Trying to get my model to work now :)