Coupled heat transfer in multi-layer participating media with diffuse reflection

Transient coupled radiative and conductive heat transfer in a three-layer absorbing-emitting participating medium composite is studied by using control volume method in combination with ray tracing method under radiative and convective boundary condition. The surfaces and interfaces of the composite are semitransparent and diffusive. The ray tracing method is used to create one-layer and two-layer radiative energy transfer models, and the radiative transfer coefficients of the three-layer participating media are deduced by tracing the energy transferring in the composite. The radiative source term in the energy equation is expressed by radiative transfer coefficients. Patankar's method is applied to linearize the radiative source term, and is given by temperature distribution of the composite solving linearized equation via tri-diagonal matrix algorithm. The influences of convective coefficient and absorbing coefficient on coupled heat transfer are investigated in detail.