【摘要】 采用氧-乙炔火焰喷涂金属粉末工艺在不锈钢基板表面制备不锈钢基多孔层,用于强化高功率电子器件沸腾水冷。研究了喷涂火焰功率对多孔层结构的影响,制备的多孔层孔隙率最高可达48.7%。建立了池沸腾实验系统,对比测试了光滑表面和多孔层修饰表面(多孔表面)在去离子水中的饱和池沸腾传热性能;并采用高速摄像机对沸腾现象进行可视化研究。结果表明:多孔表面起始沸腾过热度较光滑表面可降低1.4—2.7 K;多孔表面可显著强化沸腾传热,且强化效果随多孔层孔隙率的增大而增强,多孔表面最高传热系数为50.1 k W/(m~2·K),最高临界热流密度(CHF)为1 596.1 kW/m~2,分别比光滑表面提高了60%和30%;多孔表面汽化核心数量多,且脱离气泡不易汇聚,故表现出较好的沸腾传热特性。研究结果为该类型多孔表面用于电子冷却强化提供了一定依据。更多还原

【Abstract】 Stainless steel-based porous layer for high power electronic devices to enhance liquid boiling cooling was prepared by oxygen-acetylene flame spraying powder method. The effect of spray flame power on porous layer structure was investigated,and the highest porosity of the porous layer could reach to 48. 7%. Pool boiling experiments insaturated deionized water from both plain and porous layer modified surface(porous surface) were performed,and high speed camera was used for visualization study of bubble behaviors. The results showed that the porous surfaces could lower the incipient boiling superheat and enhance the boiling heat transfer. The incipient boiling superheat on porous surfaces is 1. 4-2. 7 K lower than that on plain surface. The boiling heat transfer performance on porous surface gets improved as the porosity increase. The highest heat transfer coefficient and the highest critical heat flux(CHF) on porous surface are 50. 1 k W/(m~2·K) and 1 596. 1 k W/m~2,60% and 30%higher than that on plain surface respectively. Visualization study of bubble behaviors shows that the porous surface has more nucleation sites,and the departed bubbles from porous surface are not easy to converge,which results in superior boiling heat transfer performance. All the results in this paper provide the basis for the application of flame-sprayed porous surface to the enhancement of electronic cooling.更多还原