CFD investigation of the effect of manifold and microchannel ratio on the hydrodynamic performance of microchannel heat sink

Flow distribution of working fluid greatly affects the performance of microchannel heat sinks (MCHSs). Uniform flow distribution prevents the development of hot spots and dead zones. Major parameters that govern the flow distribution in MCHSs are manifold and microchannel geometry. Many studies involved complicated manifold designs or novel approaches which may not be easily incorporated. Also, many researchers have examined various microchannel geometrical parameters. However, simultaneous alterations of more than one parameter is scarce. The present study focuses on the effect of simple manifold layouts, namely rectangular manifold (Rect_MCHS), circular manifold (Circ_MCHS), and triangular manifold (Tria_MCHS), and microchannel geometry, defined by microchannel ratio, a ratio of microchannel width to microchannel spacing, on the hydrodynamic performance of MCHSs using three-dimensional computational fluid dynamic (CFD). The hydrodynamic performance of MCHSs was evaluated in terms of pressure drop, velocity distribution, and coefficient of flow nonuniformity. Results showed that higher inlet flow rates and smaller microchannel ratios produced better flow distribution performance in which the latter has a higher positive impact on the hydrodynamic performance of MCHSs. Smaller microchannel ratio designs have larger microchannel spacing which served as a barrier to create flow dispersion effect. This effect was further amplified at higher inlet flow rates. Generally, Rect_MCHSs produced the best hydrodynamic performance. Furthermore, variation in temperature showed negligible impact on the hydrodynamic performance of MCHSs, compared to inlet flow rate and microchannel ratio. This suggests that studies which concern with flow distribution performance could be conducted without the energy aspect to reduce computational time.