Coupled radiation and conduction in a graded index layer with specular surfaces

The use of numerical curve ray tracing (NCRT) method for solving the radiative transfer in a graded index medium with semitransparent specular surfaces was analyzed. The influence of refractive index distribution on coupled radiation and conduction heat transfer was significant at a temperature level above 1000 K. As the radiative energy absorbed by a node near the boundary increased due to the pure heat conduction, it resulted in the increase in temperature. It was found that a linear refractive index always resulted in a higher temperature or a lower temperature and a sinusoidal refractive index always resulted in a higher heat flux or a lower heat flux.