Analytical expressions for configuration factor between cylindrical surfaces in rod bundle geometry

Contour integral technique has been applied to obtain expressions for diffuse radiation configuration factor for cylindrical geometries in a nuclear reactor fuel bundle. The cases studied are: (i) view factor between two cylindrical rods/tubes of different diameter and equal finite length, (ii) view factor between two cylindrical rods with interference from a third rod and (iii) view factor between a cylindrical rod and a concentric cylindrical enclosure, of equal finite lengths. In the literature, contour integral technique has been stated to appreciably be the more precise method than the area integration method. Present configuration factor results of finite length geometries have been compared with that of exact algebraic expressions available in the literature for infinite length. It was observed that the length of the geometry influences the configuration factor results considerably and use of infinite length approximations in finite length cases can lead to significant errors.