UDF Species source makes my temperature drop... cold fire???

therandomestname · August 2, 2011, 23:08

Hello all:

I'm simulating a biomass gasifier, and after having lots of convergence problems with the multiphase model, I decided to use source terms to add my pyrolysis and reaction products (CO and CO2) since it's a very simple model. When I turn my species and mass source terms on, the temperature drops. I believe that this is because I am adding mass and changing specific heat and Fluent is solving the energy equation. Does anybody know what the amount of heat I have to add for this is equal to? I am new to this software and I'm not sure how Fluent handles Cps, enthalpies, and the energy equation.

Thanks a lot,

John

Tleja · November 26, 2015, 12:12

Hi! john

Have you solved this problem yet?

At the moment, I have the same problem.
I also use species model with mass and energy source term. Actually,my reaction is exothermic reaction. As soon as my reactant will be consumed immediately, temperature should increase basically because of heat of reaction. I already made sure about negative or positive of energy source term.

But, Temperature in my system drop a little bit. It should increase actually.
I don't know why.

Please help me! I have been solving this trouble for many week.

Tleja

August 2, 2011, 23:08	UDF Species source makes my temperature drop... cold fire???	#1
therandomestname New Member John Join Date: Nov 2010 Posts: 11 Rep Power: 15	Hello all: I'm simulating a biomass gasifier, and after having lots of convergence problems with the multiphase model, I decided to use source terms to add my pyrolysis and reaction products (CO and CO2) since it's a very simple model. When I turn my species and mass source terms on, the temperature drops. I believe that this is because I am adding mass and changing specific heat and Fluent is solving the energy equation. Does anybody know what the amount of heat I have to add for this is equal to? I am new to this software and I'm not sure how Fluent handles Cps, enthalpies, and the energy equation. Thanks a lot, John

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November 26, 2015, 12:12		#2
Tleja Member Tleja Join Date: Sep 2013 Posts: 40 Rep Power: 13	Hi! john Have you solved this problem yet? At the moment, I have the same problem. I also use species model with mass and energy source term. Actually,my reaction is exothermic reaction. As soon as my reactant will be consumed immediately, temperature should increase basically because of heat of reaction. I already made sure about negative or positive of energy source term. But, Temperature in my system drop a little bit. It should increase actually. I don't know why. Please help me! I have been solving this trouble for many week. Tleja