You should use the non-adiabatic modeling option if your problem definition in FLUENT will include one or more of the following:
Note that the adiabatic model is a simpler model involving a two-dimensional look-up table in which scalars depend only on and (or on and ). If your model is defined as adiabatic, you will not need to solve the energy equation in FLUENT and the system temperature will be determined directly from the mixture fraction and the fuel and oxidant inlet temperatures. The non-adiabatic case will be more complex and more time-consuming to compute, requiring the generation of three-dimensional look-up tables. However, the non-adiabatic model option allows you to include the types of reacting systems described above.
Select Adiabatic or Non-Adiabatic in the Chemistry tab of the Species Model panel.