Experimental and Numerical Investigations of Thermal Hydraulic Performance in Ribbed Channel for Combustor Liner

Abstract

The present study assess the thermal hydraulic performance of V-shaped, W-shaped and 2W-shaped ribs in a rectangular channel with an aspect ratio of 6:1. The rib-roughened copper plates were located at the bottom of the channel to simulate the backside wall cooling of gas turbine combustor liners. The rib height-to-hydraulic diameter ratio (e/Dh) was 0.05834 and the rib pitch-to-height ratio (P/e) was 10 for all the cases. The experiments were carried out at the Reynolds numbers ranging from 32000 to 72000. A steady state heat transfer measurement method is used to investigate the heat transfer enhancement of ribbed wall against a smooth wall. Pressure taps were located at two stream-wise locations in channel walls to measure the pressure loss. To validate the understanding of experimental data, all the rib configurations were investigated numerically using ANSYS FLUENT. A low Reynolds number k-ε turbulence model was used to predict the heat transfer in the channel. The results show that the 2W ribs have the highest heat transfer and pressure loss characteristics in channel. It gives around 1.4–1.6 times increase in average Nusselt number and 2.7–3.3 times increase in friction factor as compare to smooth plate. Among all the cases V ribs obtained lowest heat transfer and pressure loss characteristics. Furthermore, both heat transfer enhancement and pressure loss increases with increasing Reynolds number.