Heat transfer characteristics from an array of thin strips pin fins due to their exposures to a single downward jet impingement

Abstract

This paper investigates the heat transfer characteristics from thin strips pin fins due to their exposure to a single circular downward air jet impingement. Five aluminum specimens were considered; each one has a rectangular base of 84 mm 9 78 mm and it has an array of about 300 thin strips pin fins. A test rig consists mainly of air compressor; nozzle and protractor mechanism was setup. Experiments were done to find out the effects of attack angle, Reynolds number, nozzle-to-target spacing, lateral pitch and parallel pitch among the fins on the heat transfer characteristics. Empirical correlations were deduced to describe the experimental data. A CFD-numerical model was introduced to monitor the flow characteristics on a scale of more details than that possible in the experimental work. The comparison among the results of the present work and those by the literature shows about 50% improvement in heat transfer characteristics rather than the single jet impingement onto flat plates, cylindrical surfaces, ribbed walls and multiple jets impingement onto flat plates.