Flame length overpredicted

mfmohdyasin · October 19, 2010, 05:29

Dear all,
I try to simulate methanol spray combustion in a swirl-stabilized burner using dieselFoam.
I used cylindricalInletVelocity BC for inlet gas flow, and unitInjector for methanol spray. I got very long flame--could not see the flame tip even after increasing the combustor length by factor of 5. All the boundary conditions are based on a benchmark experiment. I've tried to increase reaction rate in chem.inp file by 10 order of magnitude but no difference seen in term of flame length.

Has anyone encounter this problem before? Any 'guess' is welcomed.

Thanks,
Fairus

francescomarra · October 21, 2010, 06:43

Dear Fairus,

it is very difficult to suggest something meaningful with so few information about your simulation. I can just try to guess some possibilities in the spirit that I will certainly miss the right answer but I could promote your thoughts about the different issues involved.

Firstly it is important to check the geometry: just missing the right units (m instead of mm f.i.) could give you completely different conditions.

To have a so long flame means that you are putting much more fuel than air: how do you check your stoichiometry ? I would suggest to test the simulation by reducing the the mass flow rate of fuel.

My best regards,

Franco

October 19, 2010, 05:29	Flame length overpredicted	#1
mfmohdyasin New Member fairus Join Date: Apr 2010 Posts: 20 Rep Power: 16	Dear all, I try to simulate methanol spray combustion in a swirl-stabilized burner using dieselFoam. I used cylindricalInletVelocity BC for inlet gas flow, and unitInjector for methanol spray. I got very long flame--could not see the flame tip even after increasing the combustor length by factor of 5. All the boundary conditions are based on a benchmark experiment. I've tried to increase reaction rate in chem.inp file by 10 order of magnitude but no difference seen in term of flame length. Has anyone encounter this problem before? Any 'guess' is welcomed. Thanks, Fairus

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October 21, 2010, 06:43		#2
francescomarra Member Franco Marra Join Date: Mar 2009 Location: Napoli - Italy Posts: 68 Rep Power: 17	Dear Fairus, it is very difficult to suggest something meaningful with so few information about your simulation. I can just try to guess some possibilities in the spirit that I will certainly miss the right answer but I could promote your thoughts about the different issues involved. Firstly it is important to check the geometry: just missing the right units (m instead of mm f.i.) could give you completely different conditions. To have a so long flame means that you are putting much more fuel than air: how do you check your stoichiometry ? I would suggest to test the simulation by reducing the the mass flow rate of fuel. My best regards, Franco