Microfluidic production of silica nanofluids for highly efficient two-phase cooling with micro pin-fins structure

Abstract

Flow boiling heat transfer in microchannels is fundamentally important for the thermal management of high-power electronics. The combination of silica nanofluids and micro pin-fins structure is expected to solve the limitations of the internal trade-off between the heat transfer coefficient (HTC) and critical heat flux (CHF). However, the high cost, preparation complexity, poor stability, and particle agglomeration limit the further development of silica nanofluids. Herein, we present a simple and straightforward microfluidic strategy for continuous, ultrafast, and high-throughput synthesis of functional silica nanofluids with excellent stability. Numerical simulation and experimental validation are conducted to investigate the excellent mixing performance of spiral microreactor. The morphology and size of SiO2 can be precisely controlled by simple flow rate. The excellent stability of time (∼30 d) and temperature (∼80 ℃) significantly improved the problem of easy aggregation of nanofluid particles previously used for heat transfer. The flow boiling heat transfer in microchannels on micro pin-fins silicon chip demonstrates the simultaneous enhancement of CHF (124%) and HTC (153%) at extremely low power consumption (pressure drop less than 1.5 kPa) compared to the base fluid. These findings provide important guidelines for the embedded cooling and shed new light on significant energy savings on electronics.