16.2.1 Choosing Adiabatic or Non-Adiabatic Options

You should use the non-adiabatic modeling option if your problem definition in ANSYS FLUENT will include one or more of the following:

• radiation or wall heat transfer

• multiple fuel inlets at different temperatures

• multiple oxidant inlets at different temperatures

• liquid fuel, coal particles, and/or heat transfer to inert particles

Note that the adiabatic model is a simpler model involving a two-dimensional look-up table in which scalars depend only on $\overline{f}$ and $\overline{f^{'2}}$ (or on $f_{\rm fuel}$ and $p_{\rm sec}$). If your model is defined as adiabatic, you will not need to solve the energy equation in ANSYS 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 dialog box.