分形维数对疏水表面液滴凝固过程影响研究  

Effect of fractal dimension on process of droplet solidification on hydrophobic surfaces

作　　者：刘琰[1,2] 张磊 谢辉[2] 周亮[2] 李国豪 Liu Yan;Zhang Lei;Xie Hui;Zhou Liang;Li Guohao(School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China;Xi’an Aeronautics University,Xi’an 710077,China)

机构地区：[1]华北电力大学能源动力与机械工程学院,北京102206 [2]西安航空学院,西安710077

出　　处：《低温工程》2023年第3期71-75,88,共6页Cryogenics

基　　金：陕西省教育厅专项科研计划项目(22JK0420);陕西省科学基金(2022JQ-327);西安航空学院校级科研项目(2020KY1229)。

摘　　要：为分析疏水表面形貌参数对过冷液滴凝固过程的影响,采用化学刻蚀与氟化物改性的方法制备了疏水表面,利用图像处理技术对疏水表面微观形貌特征进行提取与分析,并对疏水表面进行凝固实验研究,获得了不同润湿性疏水表面分形维数对液滴凝固过程的影响规律。结果表明:刻蚀处理后疏水表面不同放大倍率的扫描电子显微镜(SEM)图像灰度分布基本相同,证明刻蚀制备的疏水表面具备分形特征。疏水表面粗糙度与分形维数呈正相关性,分形维数可作为预测表面润湿性的表面形貌参数。分形维数越大,液滴凝固时间越长,分形维数大于2.4时,凝固时间明显增加。提高表面疏水性,可有效降低液滴凝固过程中固-液界面上移速度。The hydrophobic surface was created by chemical etching and fluoride modification,and its microscopic morphology characteristics were extracted and analyzed using image processing technology.The solidification experiment was then conducted on the hydrophobic surface,and the influence law of the fractal dimension was used to determine how the hydrophobic surface morphology parameters affected the solidification process of supercooled droplets.The findings demonstrate that the hydrophobic surface created by etching has fractal properties since the gray distribution of scanning electron microscope(SEM)images at various magnifications is essentially the same.Hydrophobic surface roughness and fractal dimension have a positive relationship,and fractal dimension can be utilized as a surface topography metric to forecast surface wettability.The droplet’s coagulation time increases dramatically when the fractal dimension exceeds 2.4 and grows longer as the fractal dimension increases.Enhancing the surface’s hydrophobicity can successfully slow the solid-liquid interface’s upward movement during the droplet solidification process.

关 键 词：刻蚀 疏水 表面形貌 分形维数 凝固 

分 类 号：TK124[动力工程及工程热物理—工程热物理]