Modeling-Based Improvement of Microscale Liquid Jet Impingement Cooling

As high-power electronics cooling for high heat fluxes above 100 W/cm
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continues to become a more and more pressing matter, work to provide an efficient and effective cooling solution in turn also continues. In the ecosystem of active liquid cooling solutions, it is the cooling performance that is provided within a given flow rate and pressure drop budget that determines efficiency. Liquid jet impingement on the bare die has been proven to provide good cooling performance that is not impeded by the thermal resistance of thermal interface materials. However, system optimizations are also necessary to provide the desired cooling performance within the restrictions of flow rate and pressure drop. A modeling study and experimental demonstrations were done in this work to showcase improvement options within restricted operating conditions. The modeling study shows that the adjustment of inlet- and outlet-nozzle diameter, nozzle-to-target spacing, and nozzle pitch allows for optimizing the achieved heat transfer coefficient at given operating conditions. Based on this modeling study, a reference cooler and different improved demonstrators were built, and within the same budget for coolant flow rate and driving pressure drop, an improvement of effective heat transfer coefficient by 122% from 4.9 to 10.4 W/cm
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K was achieved.