微结构梯度能表面冷凝液滴的生长特性  

Characteristics of Condensation Droplet Growth on Microholed Gradient Surfaces

作　　者：费媛媛 贾志海[1] 肖昌昊 张涛[1] 陈梦谣 FEI Yuan-Yuan;JIA Zhi-Hai;XIAO Chang-Hao;ZHANG Tao;CHEN Meng-Yao(University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《工程热物理学报》2019年第4期926-930,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金资助项目(No.51776128)

摘　　要：利用疏水表面获得滴状冷凝进而提高冷凝器传热系数是目前冷凝器强化传热的重要方法。以聚二甲基硅氧烷(PDMS)为基底,采用光刻技术制备了微方孔结构的梯度能表面,分析了微方孔结构梯度能表面的冷凝液滴生长的动态过程.研究发现:由于微方孔边长的梯度变化,冷凝液滴的填孔速率不同,从而造成表面液滴的不同形态。通过冷凝液滴的表面覆盖率特征分析,进一步研究了冷凝液滴成核能垒、成核半径在表面梯度能作用下的规律.此外,分析了孔外平面液滴合并的速度特征,发现在冷凝初期,f=0.5的表面处,液滴的表面覆盖率增长速度最快,归因于梯度张力和表面结构的共同作用.It is a very important method to enhance heat transfer for dropwise condensation using hydrophobic surfaces. Microholed gradient surfaces are prepared with the polydimethyl-siloxane(PDMS) substrate using photolithography techniques. The dynamic processes of condensation droplet growth on gradient surfaces are observed. It is found that the fill rates of condensation droplets are different with the gradient variation of microholed surfaces, leading to the regular changes of droplet morphologies. According to the analysis of the surface coverage of condensation droplets, the energy barrier and radius of nucleation are further discussed. In addition, during the early stage of condensation, the maximum surface coverage is found when the area fraction is 0.5 by the speed analysis of droplets merging, due to the common influence of gradient surface tension and surface structure.

关 键 词：梯度能表面 液滴 滴状冷凝 

分 类 号：TK124[动力工程及工程热物理—工程热物理]