Numerical investigation on flow and heat transfer characteristics of U-shaped channels with side-wall column ribs

Abstract

For improving the cooling performance of U-shaped channels in the blade mid-chord region both in static and rotating states, this paper introduces the column rib spoiler structure on the side wall, putting forward the arrangement of column ribs along the radial direction in sequenced and staggered ways, as well as the vertical and inclined column ribs. The flow and cooling characteristics of this new channel (AR = 1:1) with different column rib structures and arrangements are studied in detail, considering rotational numbers varying from 0 to 0.4 at a typical Reynolds number of 10,000. The enhanced heat transfer mechanism of vertical and inclined column ribs in both arrangement modes and the coupling mechanism combined with the rotation effect are emphatically analyzed. The cooling performance of the two channels is compared in many aspects and the optimized size and layout of side-wall column ribs are obtained. Results show that the cooling method proposed can significantly improve the cooling effect of the U-shaped channel by 37.9% and 41.6% in the static state and rotating state, respectively. This study will provide important reference data for the development of high-efficient mid-chord cooling technology in gas turbine blades.