Experimental optimization of confined air jet impingement on a pin fin heat sink

A variety of nozzle configurations were tested to characterize and optimize the performance of confined impinging air jets used in conjunction with a pin-fin heat sink. Four single nozzles of different diameters and two multiple-nozzle arrays were studied at a fixed nozzle-to-target spacing, for different turbulent Reynolds numbers (5000 less than or equal to Re less than or equal to 20 000), Variations in the output power level of the heat source and nozzle-to-target spacing were found to have only modest effects on heat transfer at a fixed Reynolds number. Enhancement factors were computed for the heat sink relative to a bare surface, and were in the range of 2.8-9.7, with the largest value being obtained for the largest single nozzle (12.7 mm diameter). Average heat transfer coefficients and thermal resistance values are reported for the heat sink as a function of Reynolds number, air how rate, pumping power, and pressure drop, to aid in optimizing the jet impingement configuration for given design constraints.