Heat transfer mechanisms in an impinging synthetic jet for a small jet-to-surface spacing

Impinging synthetic jets have been identified as a promising technique for cooling miniature surfaces like electronic packages. This study investigates the relation between the convective heat transfer characteristics and the impinging synthetic jet flow structure, for a small jet-to-surface spacing H / D = 2 , dimensionless stroke length 1 < L 0 / D < 22 , and Reynolds number 1000 < Re < 4300 . The heat transfer measurements show evidence for a power law relationship between the Reynolds and Nusselt number for a constant stroke length. A critical stroke length L 0 / H = 2.5 has been identified. Using phase-resolved particle image velocimetry, vortex quantification is applied to elucidate the influence of the impinging vortex on the time-averaged heat transfer distribution.