function [F12, A1, F21, A2] = disk2cone(rd, rc, h, L) %[F12, A1, F21, A2] = disk2cone(rd, rc, h, L) % % View factor from a disk to a coaxial cone. % % Inputs: % % rd = radius of disk % rc = radius of cone % h = height of cone % L = distance from disk to cone % % Outputs: % % F12 = view factor from disk to cone % A1 = area of the disk % F21 = view factor from cone to disk % A2 = area of the cone % % 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-48.html % %========================================================================== alpha = atan(rc/h); % Cone angle A1 = pi*rd^2; l = h/cos(alpha); A2 = pi*rc*l; S = L/rd; R = rc/rd; X = S + R*cot(alpha); A = sqrt(X^2 + (1 + R)^2); B = sqrt(X^2 + (1 - R)^2); C = sqrt(cos(alpha) + S*sin(alpha)); D = sqrt(cos(alpha) - S*sin(alpha)); E = R*cot(alpha) - S; if alpha > atan(1/S) F12 = (R^2 + X^2 + 1 - sqrt((1 + R^2 + X^2)^2 - 4*R^2))/2; else F12 = (-A*B*atan((A*C)/(B*D)) + (1 + S^2)*atan(C/D) + ... (sin(alpha)/cos(alpha)^2)*(X*E*atan((C*D)/X) + ... + S^2*atan((D*D/S)) + (C*D)^2*(atan(X/(C*D)) - atan(S/(C*D)))) + ... ((R*(X + S))/sin(2*alpha) - S*R*tan(alpha))*acos(-S*tan(alpha)))/pi; end F21 = F12*A1/A2; % F12*A1 = F21*A2 reciprocity