Heat Transfer in Rotating Rectangular Channels with V-Shaped and Angled Ribs

Abstract

An experimental study was performed to measure the regionally averaged heat-transfer distributions in a rotating ribbed channel with an aspect ratio of 4:1. The Reynolds number, based on hydraulic diameter, varies from 5 × 10 3 to 40 × × 10 3 . The rotation number ranges from 0 to 0.3, and the inlet coolant-to-wall density ratio (∆ρ/ρ )i smaintained around 0.122. Six different configurations of ribs, oriented at an angle of 45 deg to the direction of flow, are placed on both the leading and trailing surfaces: 1) parallel V-shaped ribs without gaps, 2) staggered V-shaped ribs without gaps, 3) parallel V-shaped ribs with gaps, 4) parallel angled ribs without gaps, 5) staggered angled ribs without gaps, and 6) parallel angled ribs with gaps. The rib-height-to-hydraulic-diameter ratio (e/Dh )i s0.078, and the rib-pitch-to-height ratio (P/e )i s10. The channel orientation with respect to the plane of rotation is 135 deg. The results show that the V-shaped rib configuration produces more heat-transfer enhancement than the angled rib configurations. It is also shown that there is only a negligible difference between the heat-transfer enhancement due to the staggered V-shaped ribs without gaps and the enhancement due to the parallel V-shaped ribs without gaps. The same is true for the staggered and parallel angled ribs without gaps. Also, the parallel V-shaped ribs without gaps produce more heat-transfer enhancement than the V-shaped ribs with gaps, whereas the parallel angled ribs with gaps produce more heat-transfer enhancement than the angled ribs without gaps. Finally, rotation further increases the heat transfer from all surfaces above that of the stationary channels.