
The calculation method for temperature will depend on whether the model is adiabatic or nonadiabatic.
Adiabatic Temperature Calculation
For the adiabatic premixed combustion model, the temperature is assumed to vary linearly between the temperature of the unburnt mixture, , and the temperature of the burnt products under adiabatic conditions, :
NonAdiabatic Temperature Calculation
For the nonadiabatic premixed combustion model, FLUENT solves an energy transport equation in order to account for any heat losses or gains within the system. These losses/gains may include heat sources due to chemical reaction or, for example, heat losses due to radiation. The energy equation in terms of sensible enthalpy, , for the fully premixed fuel (see Equation 13.23) is as follows:
represents the heat losses due to radiation and represents the heat gains due to chemical reaction:
where  
=  normalized average rate of product formation (s )  
=  heat of combustion for burning 1 kg of fuel (J/kg)  
=  fuel mass fraction of unburnt mixture 