EFFECT OF MISSING FIN ON ENDWALL HEAT TRANSFER IN A ROTATING COOLING CHANNEL

Abstract

This paper experimentally investigated the endwall heat transfer distribution in a rotating rectangular cooling channel (Aspect ratio = 4:1) using a newly developed steady-state liquid crystal thermography. Three Reynolds numbers (5000, 10000 and 20000) were tested, and the highest rotation number was 0.65. The buoyancy parameter ranged from 0 to 1.0 at a fixed density ratio of 0.1. Effect of missing fin (one fin missing) on heat transfer in a staggered pin-fin array was studied. For the stationary case, absence of the fin contributed to an undisturbed wake region from the adjacent upstream fins. Both leading and trailing surfaces produced the asymmetric heat transfer distribution along the spanwise direction because of the channel orientation (150 degrees) and rotation. At the highest rotation number, a highly irregular Nusselt number contour was observed on the missing fin region. This was mainly attributed to the intensified rotation induced secondary flow from the enlarged fin spacing, and the heat transfer enhancement of the missing fin case was 20% higher than the full fin case on the trailing surface.