Radiation heat transfer in three-dimensional closed space including diffuse and specular surfaces - (Numerical calculation method using an improved ray-tracing method)

A method of numerical calculation for radiation heat transfer in a three-di mensional closed space including diffuse and specular surfaces was develope d. To enable an analysis of the radiation heat exchange on each surface con sidering multiple specular reflections and obstacles to radiation in the sp ace, an improved heat ray-tracing method was presented to calculate view fa ctors accurately. The method was determined to be applicable to complicated problems in test calculations using models with specular surfaces and obst acles. Continuing efforts are being applied to more realistic problems. The example examined in this paper is an infrared emitter with a parabolic spe cular reflector, which is a conventional electric heating apparatus. The me asured result for radiant power distribution agrees well with the calculate d one. The practical validity of our method was verified.