Hi. I am using CFX-11 trying to model combustion of a Methane-air mixture in a room. The boundary condition I'm trying to set up is a mass flow of gas mixture flowing normal into the domain through a circular surface in the floor of the room.

It's only possible to specify the mass flow as the b.c. The problem is that I want to set a specific heat release rate of 67.9 kW. I haven't found a way to figure out the energy release of the methane-air mixture in CFX-11 in this situation. I'm basically trying to set up the combustion simulation in the same way as Tut. 18 in CFX-11. That is, with a single-step complete combustion (Methane Air WD1 NO PDF), using the existing "Methane Air Mixture" and Eddie Dissipation combustion model.

So, if anyone has any ideas how to calculate the energy released by i.e. 1 kg of methane-air mixture in this type of combustion, it would be very appreciated.

Thanks Reine Granström

Have a look at the possible approaches to formulate the energy balance equations in combustion cases (if I remind correctly the book of Veynante and Poinsot presents both approaches). CFX defines energy as sum of heat and formation enthalpy. Within this approach you have no source term for chemical reaction in the energy transport equation. The specific heat release results simply from the enthalpy definitions of reactants and products.

With other words: due to the very convient approach of CFX its not required to waste the enthalpy of your brain for defining a heat release.

Sir,

i am ME ENERGY ENGG student, i have interest for doing my project in COMBUSTION ANALYSIS IN GAS TURBINE , i have question about how to do and it is possible to do by using CFX or any other packages should need for this analysis?