Convective heat transfer of a row of air jets impingement excited by triangular tabs in a confined crossflow channel

Computational and experimental studies were conducted to investigate the conjugated convective heat transfer produced by single row of impinging jets inside a confined channel with non-uniform initial crossflow issued from discrete holes. The effects of the crossflow-to-jet Reynolds number ratio and crossflow holes arrangement (inline or staggered in relative to the impinging jet holes) on the jet impingement behaviors were studied providing the same total cooling air mass flowrate. Particular attention was paid to examine the tab-excited jet impingement behaviors in a confined channel with non-uniform crossflow. The results show that the tabbed excitation on the improvement of convective heat transfer in the vicinity of impingement region is not as well as the situation where no initial crossflow is present. For the inline arrangement of crossflow holes, the location corresponding to the peak laterally-averaged Nusselt number is moved downstream and the peak laterally-averaged Nusselt number is decreased significantly under larger crossflow-to-jet Reynolds number ratios. While for the staggered arrangement of crossflow holes, the location corresponding to the peak laterally-averaged Nusselt number is not affected by the crossflow but the peak laterally-averaged Nusselt number is decreased monotonously with the increase of crossflow-to-jet Reynolds number ratio. Under small crossflow-to-jet Reynolds number ratio, the initial crossflow arrangement has little influence on the laterally-averaged Nusselt number distribution. Among three crossflow-to-jet Reynolds number ratios ranged from 0.5 to 2, the maximum relative difference of peak laterally-averaged Nusselt numbers between two different crossflow arrangements is occurred under crossflow-to-jet Reynolds number ratio of 1. (C) 2014 Elsevier Ltd. All rights reserved.