Heat transfer between rotating sphere and spherical-surface heat sink

Abstract

To cool a heated rotating sphere, a heat sink with spherical surface is designed which is situated at a small distance from the sphere; thus, a small curve surface air gap is formed between them which will be used to transfer the heat from the rotating sphere. The numerical simulation method was used to investigate the flow and heat transfer capability of the small air gap. In the entire flow region, a regular Eulerian grid was adopted to solve the modified momentum and energy equations simultaneously. In the region that was occupied by the rotating sphere, a moving Lagrangian grid was used, which tracks the rotational motion of the sphere. A Reynolds function and an energy function were introduced to represent the momentum interaction and thermal interaction between the sphere and the fluid. The heat transfer rate and the flow characteristics of the air gap were presented. The influence of rotating speed and eccentricity as well as the radius of curvature on the flow were quantitatively investigated. It was found that the heat transfer strengths could be adjusted by changing these parameters. It was also observed that the eccentricity and the rotating speed exert significant influences on the heat transfer.