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/spl les/Re/spl les/20000). 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 flow rate, pumping power, and pressure drop, to aid in optimizing the jet impingement configuration for given design constraints.