Specular Reflection Allowing Reduction and Calculation of Radiative Heat Transfer

Configurations similar to ’V-Grooves’, as already applied for radiators, can also insulate complete spacecraft and telescopes from solar radiation or hot modules several orders of magnitude better than the usual MLI. The specularity of surfaces contributes to the reduction of the radiation between the shields and thus improves the insulation. In this paper absorption factors between specularly and diffusely reflecting conical and rectangular areas are presented versus the ’V-angle’ in order to design such insulating configurations.

Monte Carlo methods cannot be applied for very complex configurations if the number of surfaces is too large. The introduction of auxiliary areas with 100% specular reflectivity helps to simplify these geometries. Herein, the principle of this technique is first explained and proven by two examples of V-grooves. Then this method is applied for a specific configuration: three parallel plates which each have more than 8000 holes. The results are compared with analytical equations which are valid for the special condition that the holes in each plate are distributed randomly.