This paper presents a study of different biporous evaporators as potential candidates for cooling high-power electronic devices. A biporous evaporator has two characteristic pore size distributions, which due to an enhancement in capillarity and vapor permeability greatly increase the critical heat flux (CHF) of the evaporator. In this work, eleven biporous evaporators are made by sintering together clusters of copper particles. Particles with diameters of 58, 76, 83, and 98μm are sintered into clusters with diameters of 302, 605, and 855μm. Clusters are subsequently sintered into evaporators with constant thickness-to-cluster diameter ratios of 3.3 and 0.32cm2 evaporator area. Finally, they are tested with degassed distilled water at 0.07bar. The highest CHF, 471W/cm2 at 149°C wall temperature and 104°C superheat, is measured for the 855/58 evaporator. A comparison of heat fluxes removed at a constant wall temperature of 125°C for all eleven evaporators shows that the highest heat flux of 388W/cm2 is removed with the 302/83 evaporator. A statistical regression analysis on heat fluxes at 125°C wall temperatures for all evaporators tested yields a correlation that relates the heat fluxes to cluster and particle diameters and is further used to predict a region of particle and cluster diameters with the highest heat flux.

Volume Subject Area:
Heat Transfer
Keywords:
biporous evaporator, high-power electronics cooling
Topics:
Heat, Particulate matter, Critical heat flux, Flux (Metallurgy), Wall temperature, Heat flux, Capillarity, Computer cooling, Cooling, Copper, Permeability, Regression analysis, Sintering, Vapors, Water
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