function [F12, A1, F21, A2] = frustum2base(rb, rt, h) %[F12, A1, F21, A2] = frustum2base(rb, rt, h) % % Description: % % View factor between the interior wall of a conical frustum and % its base. % % Inputs: % % rb = radius of base % rt = radius of top of conical frustum % h = height of the conical frustrum % % Outputs: % % F12 = view factor from interior wall to base % A1 = area of the interior wall % F21 = view factor from base to interior wall % A2 = area of the base % % Reference: % % A Catalog of Radiation Heat Transfer Configuration Factors, % third edition, John R. Howell, The University of Texas at Austin % % http://www.thermalradiation.net/sectionc/C-111.html % %========================================================================== if rb <= rt error('frustum2base: Base radius = %f, must be greater than top radius = %f.',rb,rt) end A1 = pi*(rb + rt)*sqrt((rt - rb)^2 + h^2); % Area of the wall A2 = pi*rb^2; % Area of the base H = h/rt; R = rb/rt; X = 1.0 + R^2 + H^2; F12 = (2*R^2 - X + sqrt(X^2 - 4*R^2))/(2*sqrt(X - 2*R)*(1 + R)); F21 = A1*F12/A2; % F12*A1 = F21*A2 reciprocity