Study of convective cooling of fin arrays using Schlieren imaging and CFD analysis

Electronic component cooling is achieved mainly through the provision of fin arrays as heat sinks located on the processing components. This paper aims to present a methodology to relate convection current characteristics obtained from Schlieren imaging with heat transfer characteristics for fin arrays. For this experiment, fin arrays were fabricated for various fin heights, fin spacings, fin widths and convection current footage for all these configurations was recorded. The velocity values obtained from the Schlieren footage was compared with computational fluid dynamics (CFD) simulations of the fin arrays and were found to be consistent. The plume velocity is related with parameters like surface temperature and average heat transfer rate. It is observed that increasing fin height (h) increases heat transfer rate and plume velocity, up to 12mm beyond which fin array choking causes a decrease. Varying the fin spacing (s) keeping fin width (t) constant yields an optimum output at 5 fins and this trend can also be explained by fin choking effects. Varying the number of fins, and fin width, with a constant spacing cause comparatively small changes in heat transfer rates and plume velocity, suggesting that fin spacing is more significant of a factor than fin thickness.