Liu Houli, Gu Zhonghao, Liang Jun
School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China.
College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241002, China.
Materials (Basel). 2023 Sep 25;16(19):6391. doi: 10.3390/ma16196391.
Surface porosity is an important means of enhancing boiling heat transfer. In this paper, two kinds of composite porous structures of surface micropore + square channel and framework micropore + square channel were prepared by selective laser melting technology using AlSi10Mg as the powder material. The effect of composites with different pore forms on boiling heat transfer was investigated in pool boiling experiments. It was found that controlling the thickness of the powder layer manufactured by selective laser melting can change the surface roughness of the sample, and the sandblasting treatment reduced the surface roughness of the samples. The average heat transfer coefficient of the rough surface composite porous structure sample was increased by 40% compared to the sandblasted sample. The micropores on the surface of the sample and inside the framework significantly enhanced the heat transfer coefficient of the composite porous structure. The presence of surface micropores increased the heat transfer area and the vaporization core density of the composite porous structure and exhibited excellent heat transfer coefficient improvement in the low heat flux region. The framework microporous composite porous structure can form effective gas-liquid diversion at high heat flux and obtain higher heat transfer performance. The large channel in the composite porous structure is the key control factor of the critical heat flux.
表面孔隙率是强化沸腾传热的重要手段。本文以AlSi10Mg为粉末材料，采用选择性激光熔化技术制备了表面微孔+方形通道和骨架微孔+方形通道两种复合多孔结构。通过池沸腾实验研究了不同孔隙形式的复合材料对沸腾传热的影响。研究发现，控制选择性激光熔化制造的粉末层厚度可以改变样品的表面粗糙度，而喷砂处理降低了样品的表面粗糙度。粗糙表面复合多孔结构样品的平均传热系数比喷砂处理后的样品提高了40%。样品表面和骨架内部的微孔显著提高了复合多孔结构的传热系数。表面微孔的存在增加了复合多孔结构的传热面积和汽化核心密度，并且在低热流区域表现出优异的传热系数提升效果。骨架微孔复合多孔结构在高热流时能形成有效的气液导流，从而获得更高的传热性能。复合多孔结构中的大通道是临界热流的关键控制因素。
