Computation of radiation view factors for surfaces with obstructed views of each other

Radiation calculations begin with a determination of view (or shape) factors describing the geometrical configuration of the exchanging surfaces. These viewfactor calculations can be very involved, time consuming and expensive. This paper describes the development of an algorithm for situations in which the view between two surfaces is obscured by one or more intervening surfaces. A technique based upon the combination of the Contour Integration and Double Area Integration methods and the acceleration techniques necessary for its efficient use are described. Numerical examples are given to demonstrate the use of the technique and to describe some of the problems inherent in treating radiation in enclosures.