linearization of radiative energy source term

Nuray Kayakol

A question about linearization of radiative energy source term ? So that it can be incorporated in a CFD code (SIMPLER ALGORITHM).

S=ka(4EB-G) to be used as a source term in the energy equation Where ka=absorption coefficient

EB=blackbody gas emissive power

G= irradiance

S can be linearized as

S= SU + SP x (Variable under consideration? enthalpy or intensity)

What will be the expressions for SU & SP and the logic behind them?

thank you for your time

nuray kayakol