Study on Flow Boiling Characteristics in Porous Open Microchannels
The rapid development of technology has led to an increasing heat generation and heat flux density in electronic or energy-storage devices.Efficient heat removal is crucial for ensuring the reliability of system operation.Among various cooling methods,flow boiling in microchannels is considered as one of the most promising heat dissipation techniques.Further enhancing the heat transfer performance of two-phase microchannel heat sinks is of significant importance.In this study,an open microchannel heat sink was fabricated using a porous material substrate sintered with 45 μm diameter spherical copper powder particles.Deionized water was used as the working fluid to investigate the flow boiling characteristics in the porous open microchannels.Three flow patterns were observed within the range of operating conditions in this study,including bubbly flow,slug-annular flow,and periodic stratified flow.The porous substrate exhibits an enhanced effect on flow boiling heat transfer at low mass fluxes,while the opposite effect was observed at high mass fluxes.This indicates the coupling and competitive influence of the porous substrate on the various heat transfer mechanisms including phase-change heat transfer,single-phase convective heat transfer,and solid conduction heat transfer.However,the positive effect of the porous material on the heat transfer performance of open microchannel flow boiling becomes more prominent with increasing heat flux and wall superheat.
porous substrateopen microchannelsflow boilingheat transfer and pressure drop characteristics
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