Numerical study of laminar heat transfer and pressure drop characteristics in a water-cooled minichannel heat sink

With the rapid development of IT industry, the heat flux in IC chips has almost reached its limit about 100W/cm. Some applications in high technologies require heat fluxes well beyond such a limitation. Therefore the search of a more efficient cooling technology becomes one of the bottleneck problems of the further development of IT industry. The micro-channel flow geometry offers large surface area of heat transfer and a high convective heat transfer coefficient. However, it has been hard to implement because of its very high pressure head required to pump the coolant fluid though the channels. Normal channel size could not give high heat flux although the pressure drop is very small. Mini-channel can be used in heat sink with a quite high heat flux and a mild pressure loss. Mini-channel heat sink with bottom size of 20mmx20mm is analyzed numerically for single phase laminar flow of coolant water through small hydraulic diameters. The effect of channel dimensions, channel fin thickness, bottom thickness and inlet velocity on the pressure drop, temperature difference and max allowable heat flux are presented. The results indicate that a narrow and deep channel with thin bottom thickness and relative thin channel fin thickness results in improved heat transfer performance with a relative high but acceptable pressure drop. A nearly-optimized structure of heat sink is found which can cool a chip with heat flux of 256 W/cm(2) at a pumping power of 0.205W.