Combustion problem, Temp to high.
 

Hello everyone,

I'm trying to model an HVOF thermal spray process, but I'm having some difficulty. I'm getting temperatures in excess of 4500K when the flame temperature of propylene is approx. 2300K.

The model is using ideal-gas as it is a supersonic flow and the standard k-e model for turbulence. The boundary condition for the fuel inlet is a propylene-oxygen mixture. I suspect this may be my proplem. I've done some other cases involving separate fuel and oxygen supplies with better results.

Any thoughts?

Devin

Re: Combustion problem, Temp to high.
 

Are you using a radiation model to get rid of some energy? That might help.

Re: Combustion problem, Temp to high.
 

Flame temperature of propylene 'WITH AIR ' may be approx. 2300K, but flame temperature 'WITH OXYGEN' might be higher than 4500K.

Sincerely, Jinwook

Re: Combustion problem, Temp to high.
 

What will the flame temperature be for kerosene and how does one go about determining the value? If I am simulating a combustor, how do i know if the flame temperature is too high?

Re: Combustion problem, Temp to high.
 

Adiabatic flame temperature of most fuel with 'AIR' as oxidant is about 2000C(~2300K) or higher.

Theoretically, Adiabatic flame temperature of most fuel with OXYGEN as oxidant might be higher than 4000K. But this is only theoretical value. In general they say that, in real experiment, the flame temperature is lower than 4000K because of dissociation.

Calculation of Adiabatic Flame Temperature(AFT) :

Q_in = Integral from T_ref to T_aft dot M Sigma (Cp)_i dot m_i dT

Where,

dot M : total mass flow rate dot m : mass fraction of each species Cp_i : specific heat of each species ...... ......

Sincerely, Jinwook

Re: Combustion problem, Temp to high.
 

Thanks, everyone, for your input. Greatly appreciated.

Devin

Dear Devin,
I am modeling the HVOF process in fluent and I am also getting very high temperature. I hope u got the solution for that. Could u please tell me the solution for getting the temperature around 2500.
Thanks

Hello Devin I am simulating HVOF aswell on Fluent and I am having some issues Could I get some information on your case set up as my results so not look very realistic