A Study on Local Heat Transfer Enhancement in a Rectangular Dimpled Channel With a Large Aspect Ratio

Abstract

In this paper the convective heat transfer in a rectangular dimpled channel with an aspect ratio of six is studied. Applications could be for gas turbine vanes, vane shrouds, ring segments and hot components in the combustor. Basic heat transfer experiments have been performed using heater foils and a steady-state method with liquid crystals. The cooling effect is achieved by a dimple configuration combined with rib turbulators. The specific subject of this study is to focus on the heat transfer enhancement in the corner regions of the dimpled large aspect ratio channel. Different configurations of rib turbulators are investigated at different Reynolds numbers. Detailed heat transfer distributions are presented for the different configurations, showing the local effect of turbulator placement and angle with respect to the main flow direction. They are complemented by pressure drop measurements and compared with numerical simulations. It is shown that locally implemented rib configurations can enhance the heat transfer in these critical regions without large pressure loss penalties.

Flow and Heat Transfer in the Tree-Like Branching Microchannel with/without Dimples

“…Shen et al [ 15 ] experimentally and numerically studied the heat transfer and pressure drop characteristics in blade trailing edge trapezoidal and rectangular cooling passages with dimples under the effect of ejection slots. Lauffer et al [ 16 ] set up a rectangular dimpled channel for gas turbine hot components and designed different configurations of rib promoters in the corner regions to heat transfer enhancement. Chang et al [ 17 ] reported on heat transfer and pressure drop features of radially rotating ribbed channels with and without dimples.…”