A numerical study of effects of the swinging amplitude of fins on heat transfer characteristics in a flow

Abstract

A new method for enhancing heat transfer of a finned heat sink is proposed in this study. In this method, extremely thin fins are installed in the finned heat sink, and these fins may swing back and forth in a flow because of the fluid flowing pass them. As a result, the velocity and thermal boundary layers attached on the fins are then contracted and disturbed, and the heat transfer rate of the fins can be enhanced. The variations between the fluid and fins are dynamic and belong to a kind of the moving boundary problems. The arbitrary Lagrangian-Eulerian (ALE) kinematic description method is available and adopted to describe the flow and thermal fields, and the governing equations are solved using the Galerkin finite element method with moving meshes. The effects of variations in the Reynolds number, swinging speed and amplitude of the fins on the heat transfer of the fins are investigated. The results show that the velocity and thermal boundary layers may be contracted and disturbed as the fins swing with a large speed, and the heat transfer rates are remarkably affected by the swinging speed and amplitude of the fins.