Experimental characterization of a hybrid impinging microjet-microchannel heat sink fabricated using high-volume metal additive manufacturing

A high-performance water-cooled micro heat sink for the thermal management of high heat flux microelectronics was designed, fabricated, and tested. The heat sink design leverages a multi- metal electrodeposition additive manufacturing process to produce complex flow which are impossible to fabricate with traditional processes. A previous study employed simulation-driven design to develop and optimize micro heat sinks and is a hybrid of microchannels with an array of integrated microjets. In the present investigation, a prototype heat sink was fabricated and tested at heat fluxes up to and exceeding 1000 W/cm2. The results demonstrate reasonable agreement between the numerical predictions and experimental results, considering the complex geometry flow and conjugate heat transfer within the device. From a thermal–hydraulic performance standpoint, the heat exchanger achieved an estimated overall thermal conductance of ~330 kW/m2K with a pressure drop of 160 kPa (23 psi) for a flow rate of 0.5 L/min. For inlet water at 20 °C, this corresponded to a measured base temperature of 54 °C at an applied heat flux of 1000 W/cm2. The hybrid microchannel–microjet heat sink further exhibited an enhancement ratio of 6 when compared with a microchannel heat exchanger of commensurate design. To the extent of our knowledge, this microfluidic heat exchanger has achieved one of the highest effective thermal conductance levels reported in the literature and has done so at moderate pressure drop and flow rate.