Basement Car Park Comparison between FDS and FLUENT

[DenXX]

Dear all,

I've modeled a basement car park fire scenario(system with jet fans, mechanical supply and exhaust air) using FDS and comparing the results generated by FLUENT.

The main inputs are as:

Fire size: 4MW Polyurethane

HRRPUA:400kW/m2

Soot: 10%

Simulation time: 1200s

However, comparing both side, the results(visibility, temperature) are largely different from both software. FDS may fail the visibility criteria at initial t=100s, where FLUENT results show good visibility >10m. Fire temperature shown at FLUENT is also much higher (300dg C) compare to FDS (180dg C). 

Understand that both are different software, however how could the results generated be so much difference? Any one have done similar comparison before, would appreciate if you could give some opinions.

Thanks

Den

[Mohamed ASSAL]

Hi DEN 

Here you are comparing two CFD codes Fluent and Fds we don't know how did you simulate your problème, no idea about the both set up.

Cheers Mohamed.

2013/7/25 DenXX <x_x_...@hotmail.com>

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[dr_jfloyd]

What have you done to validate that either your FDS model or your FLUENT model results in an adequate representation of the car park fire? For example:

Have you used either model to simulate an actual experiment?
Did you did a grid study?
Have you done any work to ensure that the way you model the fire (grid size, fuel definition, etc) results in expected plume and ceiling jet behavior?
How have you validated that your jet fan inputs result in the correct calculation of air entrainment by the jet?

[Mohamed ASSAL]

Just curious how did you specify the HRR with fluent:  4MW Polyurethane??? 

2013/7/25 Mohamed ASSAL <assa...@gmail.com>

[Mohamed ASSAL]

could you share some results?? or a comparaison table.

2013/7/25 Mohamed ASSAL <assa...@gmail.com>

[Chris]

I think the main difference is how soot is generated in the two CFD-codes.

[dr_jfloyd]

There are far many more differences between Fluent and FDS than just how soot might be generated: mesh generation, the assumptions in the underlying equations, the numerical solver, turbulence models, the combustion model, the radiation model, ...

[DenXX]

All

Thank you for the suggestions. I will look further in detail on all the parameters detail