Investigation of the thermohydraulic performance of impinging jet solar air heater

Jet impingement is an established method of convective heat transfer from the heated surface to the carrier fluid. High heat transfer rates are achieved using impinging jets in solar air heater duct but at the cost of increased friction power penalty. This paper presents thermohydraulic performance of impinging jet solar air heater in the form of effective efficiency and compared the same with that of conventional solar air heater. The study has been carried out to study the effect of Reynolds number, diameter of the jet, streamwise and spanwise pitch on effective efficiency. Based upon the study, it has been concluded that impinging jet solar air heater performs better than the conventional solar air heater for specified range of Reynolds number. The effective efficiency has been computed based upon the correlations developed by the investigators and maximum effective efficiency of 70% has been achieved for impinging jet solar air heater in the range of investigated system and operating parameters. Also, based upon the study, the design plots have been prepared for each jet parameter with temperature rise parameter in order to obtain optimum effective efficiency for desired value of temperature rise.

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