Radiative heat transfer control by grating composed of rarallel elliptical cylinders (energy collimation in direction normal to plane surface of grating)

摘要

A new technique for control of radiation heat transfer, i.e., the technique using a grating composed of a row of elliptical cylinders is proposed in this study, in place of the V-groove cavities previously investigated(e.g., Masuda, 1980). How the radiative energy emitted from a black base surface can be concentrated by the grating placed in front of the black base in direction nomal to the grating plane has been theoretically studied. An analysis is made for the radiation transfer system including the grating, and the solutions of the intensity of radiation in the system are obtained. With the intensities obtained and the intensities of the black base, the apparent directional emissivities of the grating are calculated. In addittion, the apparent hemispherical emissivity #epsilon#_a, h and the limiting angle #eta#_L, expressing the amount of radiative energy across the grating and the degree of concentration or collimation, respectively, are obtained. The characteristics of the radiative heat-transfer control by the grating are presented. The relation between #epsilon#_(a,h) and #eta#_L is also illustrated with a chart.