Heat Flux Distribution on a Finned Fuel Pin

Abstract

An analytical model has been developed to describe the surface heat flux distribution around a finned fuel-element simulator (FES). The heat leaving through the fin root is considered to be the sum of the radial heat flow from the internal heater underneath the fin root and the circumferential heat flow entering from the sheath adjacent to the fin root. The analysis is based on a superposition method of two one-dimensional conductive heat transfer components in radial and circumferential directions at the fin root. A numerical solution from the MARC computer code was used to demonstrate the validity of the analytical model. Single-phase heat transfer coefficients obtained from our experiments were used as boundary conditions. The surface heat-flux distribution along the periphery of the finned pin was predicted from the analytical model. The predictions were in good agreement with those from the MARC simulation for various thermalhydraulic conditions. The sheath and the fin tip temperatures calculated by the analytical model and MARC also agreed well with the experimental results.