Heat transfer of impinging jet array over concave-dimpled surface with applications to cooling of electronic chipsets

Heat transfer measurements over the impinging surface roughened by concave dimples for a 4 × 3 in-line jet array with jet Reynolds number (Re) and separation distance (S/Dj) varying in the ranges of 5000 ⩽ Re ⩽ 15,000 and 0.5 ⩽ S/Dj ⩽ 10 are performed. For each tested Re and S/Dj combination, the heat transfer data acquired from three eccentricities (E) between jet-centre and dimple-centre of 0, 1/4 and 1/2 dimple-pitch (H) is analyzed. A set of selected experimental data illustrates the isolated and interactive influences of surface topology, Re, S/Dj and E/H ratio on local and spatially averaged heat transfers. In conformity with the experimentally revealed heat transfer physics, the empirical heat transfer correlations that permit the evaluation of spatially averaged Nusselt number over the central jet region of the concave-dimpled surface with E/H ratios of 0, 1/4 and 1/2 are generated.