Two-dimensional radiative heat transfer in a planar layer bounded by nonisothermal walls

The emissive power and radiative flux at the boundaries are calculated for a two-dimensional, finite, planar, gray, absorbing-emitting-scattering medium bounded by nonisothermal black walls. The medium is in radiative equilibrium and the scattering phase function is composed of a spike in the forward direction superimposed on an isotropic background. Exact radiative transfer theory is used to formulate the problem. Using the principle of superposition, the results for any step variation in the wall temperatures are expressed in terms of universal functions for the semi-infinite step variation in wall temperature. Thus, many different wall temperature distributions can be handled. The results are also directly applicable to a nongray medium with spectral windows.