Heat transfer in rotating rectangular channels (AR=4:1) with V-shaped and angled rib turbulators with and without gaps

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 a hydraulic diameter, varies from 5,000 to 40,000. The rotation number ranges from 0 to 0.3, and the inlet coolant-to-wall density ratio ([Delta][p]/[p]) is maintained around 0.122. Six different configurations of ribs, oriented at an angle of 45⁰ to the direction of flow, are placed on both the leading and trailing surfaces: parallel and staggered V-shaped ribs without gaps, parallel and staggered angled ribs without gaps, parallel V-shaped ribs with gaps, and parallel angled ribs with gaps are considered. The rib height-to-hydraulic diameter ratio (e/D[h]) is 0.078, and the rib pitch-to-height ratio (P/e) is 10. The channel orientation with respect to the plane of rotation is 135⁰. The results show that V-shaped rib configuration produces more heat transfer enhancement than the angled rib configurations. It is also shown that there is only 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, while the parallel angled ribs with gaps experience overall greater heat transfer enhancement than the angled ribs without gaps. Finally, all surfaces undergo heat transfer enhancement by rotating the channel compared to the stationary channel for all cases.