An experimental heat transfer investigation of an impingement jet array with turbulators on both target plate and impingement plate

Abstract

Impingement cooling has been widely used for high heat transfer demanded applications, and numerous attempts have been made to improve its thermal efficiency. This study presents experimental heat transfer results of an innovative rib configuration combined by V-ribs on the impingement plate and detached ribs on the target plate for an inline impingement system. The combined ribs are expected to redirect the spent air in the impingement channel, modify the cross-flow field and thus, improve the heat transfer performance. The transient thermochromic liquid crystal (TLC) method is employed for detailed heat transfer measurements. Pressure taps set along the test rig are used to evaluate the pressure loss. In addition, the thickness and roughness effect of the sprayed coating layers (TLC and black paint) is experimentally studied. The detached rib configuration is determined based on a geometrical parameter study on the rib position. The effect of the combined ribs is investigated for different jet Reynolds numbers and different separation distances. The results show that the combined ribs induce a Nusselt number increase for all cases in the studied range, with a negligible extra pressure loss. A relatively thin and smooth sprayed coating is employed, to ensure the measurement accuracy.