Radiation Heat Transfer between Two Surfaces Taken into Consideration the Directional Property of Emittance（Part 1） 　−In Case One Surface Is of the Low Temperature Blackbody−

The approximate calculations of radiation heat transfer between two surfaces，on the assumption that the emissive property of each surface is nondirectional as on the blackbody or the graybody，have usually been made by means of the configuration factor determined only by dimension， shape and angle relation of those surfaces. However，if the emittances of the real surfaces of solids have the directional properties，then the configuration factor must be determined by taking into consideration not only dimension，shape and angle relation but also the directional factor In this study， as an example of the simplest case， the calculation of radiative heat transfer between a surface possessing the directional property on the emittance and a surface of low temperature blackbody was tried out