Heat Transfer Intensification of a Confined Impinging Air Jet Via a Guiding Baffle

Abstract

The heat transfer intensification of a confined impinging jet was achieved using a rough surface or pin fins as well as using modified nozzles such as chamfering, chevron, sweeping, swirling, etc. In this work, an enhanced cooling process utilizing a single confined air jet impinged on a flat plate using a guiding baffle is implemented. The impacts of Reynolds number (Re) ranged from 500 to 5000, guiding baffle diameter-to-nozzle diameter (D/d) of 2, 4, and 6, and guiding baffle height-to-nozzle to impinging plate distance (h/H) of 1/3, 1/2, and 3/4 on the cooling process are studied. The distributions of surface temperature are acquired experimentally using a thermal infrared camera. As well, the local Nusselt number (Nu), stagnation point Nusselt number (Nust), average Nusselt number (Nu¯), and average Nusselt number ratio (Nu¯r) are evaluated. The results reveal that the enhancement of heat transfer is achieved due to installing a guiding baffle with a D/d of 2 for all values of baffle height and Reynolds number. In addition, the Nu¯r is increased with increasing the Re in the range from 500 to 2500, then it is decreased by a further increase in Re. Moreover, based on the experimental results, an empirical correlation is proposed to compute the Nu¯ depending on Re, D/d, and h/H with a ±2.65% standard deviation.