[cunconbkhp]

Dear all,

I'm currently learning to use the solver fireFoam. I want to apply this solver for some fire safety projects. I have to evaluate the performance of fireFoam with FDS code.

i'm testing the smallPoolFire3D tutorial. The code runs OK but the Heat release rate is overestimated. I haven't modifies the tutorial, just add function in controlDict to calculte the HRR by volIntegrate of Qdot.

the pool fire area is 0.2 m * 0.2 m = 0.04 m2. The velocity of the methane flux is 0.01 m/s. The density of CH4 is 0.656 kg/m3. The heat of combustion of CH4 is about 50000 kJ/kg. So with the hand calcul, a HRR max of : 0.01*0.2*0.2*0.656*50000 = 13 kW is expected.

However the HRR max caculated with function is 28 kW. The overestimaiton of HRR was notified with older versions of OpenFoam (i've read others topics in the forum). I'm using the OpenFoam 2106. I'm very suprised that this error is still present. In all the tutorials provided, there aren't any measure for HRR???

Please help me if you know any method to repare the problem.

If i'm not wrong, the unit of Qdot is J/m3/s

functions
{

HRR_vol
{
type volFieldValue;
//functionObjectLibs ("libfieldFunctionObjects.so");
libs ("libfieldFunctionObjects.so");
log true;
writeControl adjustableRunTime;
writeInterval 2e-2;
writeFields false;
regionType all;
operation volIntegrate;
enabled true;
fields
(
Qdot
);
}
}

Thanks

[cunconbkhp]

Hi all!

I've tested others tutorials and found a solution for my problem :

+ use mass flow rate for the velocity
+ and use the boundary condition of type totalFlowRateAdvectiveDiffusive for the fuel mass fraction.

It's the only combination which give me a good estimation of HRR for the smallPoolFire3D case.

You can study the compartment fire tutorial. My OpenFoam version is 2106.