Characteristics of Rosseland and P-1 approximations in modeling nonstationary conditions of convection-radiation heat transfer in an enclosure with a local energy source

Numerical modeling is performed for nonstationary conjugate convection-radiation heat transfer in an enclosure with a local energy source under nonlinear heat exchange with the environment. Two approximations were used for mathematical description of the mechanism of radiation in a gas cavity, namely, Rosseland approximation and differential formulation (or P-1 approach) of the methods of spherical harmonic functions. Comparison of two different approaches to description of the radiation mechanism of energy transfer has made it possible to identify special features of thesemodels. Temperature and stream distribution functions are obtained in a wide range of the governing parameters.