Experimental study on flow boiling heat transfer characteristics of porous pin-finned array structures
The instability of pressure and temperature in flow boiling could easily lead to earlier reaching of drying limit of microchannels.A comparative study on supercooled flow boiling heat transfer experiments for sintered pin-finned array structures was performed using deionized water as the working fluid.The pin-finned structure was sintered with 30 μm,90 μm and 150 μm spherical copper powder,and the inlet water temperature was maintained at 60℃.The results show that particle size has a significant effect on heat transfer coefficient and critical heat flux qCHF of flow boiling in porous microchannels.The PF-150 sample showed the lowest wall superheat at high heat fluxes at a mass flux of 52 kg·m-2·s-1,and its qCHF reached 134 W·cm-2.The visualization results show that the larger particle size samples presented lower pressure amplitude and more-ordered pressure fluctuation,which improves the boiling heat transfer performance of the pin-finned array.Increasing mass flux can move the wet-drought boundary backwards to ensure adequate liquid supply in the rear part,and greatly reduce the instability of flow boiling.The results indicate that the sintered pin-finned array has great potential in improving flow boiling performance.
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