Heat transfer from novel target surface structures to a normally-impinging, submerged and confined water jet

Contemporary electronic systems generate high component-level heat fluxes. Impingement cooling is an effective way to induce high heat transfer coefficients in order to meet thermal constraints. The objective of this paper was to experimentally investigate the heat transfer from five novel target surface structures to a normally-impinging, submerged and confined water jet. The five target structures were: a 90° vane; a 4x4 pin fin array; and three geometries which turn the flow away from, and back towards, the surface to be cooled. The experiments were conducted for Reynolds numbers of 500 ≤ Re ≤ 24 000. The confined impinging jet was geometrically constrained to a round, 8.5mm diameter, square-edged nozzle at a jet exit-to-target surface spacing, of H/D = 0.5. The heat transfer characteristics of the five novel target surfaces were non-dimensionally compared to a flat surface, and enhancements of up to 120% were recorded. Increases of up to 45% was noted when the surface area augmentation of the target surface structures was factored out. The findings of the paper are of practical relevance to the design of primary heat exchangers for high-flux thermal management applications.