NUMERICAL SIMULATION OF CONDUCTION HEAT TRANSFER IN A SYSTEM OF SLOWLY ROTATING CONCENTRIC SHELLS SEPARATED BY SMALL ANNULAR GAP DISTANCES

Abstract

Conduction dominated heat transfer in a system of concentric shells with a very small annulus distance and surface eccentricities is studied numerically using IDEAS TMG^TM in conjunction with a user-programmed subroutine to model the heat transfer across the gas layer as a function of eccentricity and rotation rate. Sphere diameters range from 30 cm to 40 cm, annular gap sizes range from 0.5 mm to 1 mm, and eccentricities range from 0.05 mm to 0.25 mm. External thermal gradients are found to be attenuated significantly. The inner surface temperature deltas increase by a factor of 4.5, for a doubling in the eccentricity. A correlation for the effective heat transfer across the inner spheres also is presented.