微气流作用下多孔表面液滴动态润湿行为  

Dynamic wetting behavior of droplets on the surface of porous materials with micro-airflow

作　　者：党超 丁艺 贾力 彭启 Chao Dang;Yi Ding;Li Jia;Qi Peng(Institute of Thermal Engineering,School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China;Beijing Key Laboratory of Flow and Heat Transfer of Phase Changing in Micro and Small Scale,Beijing 100044,China)

机构地区：[1]北京交通大学机械与电子控制工程学院热能工程研究所,北京100044 [2]微细尺度流动与相变传热北京市重点实验室,北京100044

出　　处：《科学通报》2021年第1期128-136,共9页Chinese Science Bulletin

基　　金：国家自然科学基金(51776015);中国博士后科学基金(2019TQ0025,2019M660017)资助。

摘　　要：基于对附加动量力场调控液滴润湿行为特性的创新性思考,通过可视化实验,利用多孔材料表面配合辅助微气流作用的形式,探索了液滴在多孔材料表面的动态润湿行为特性,鉴别了微气流作用下液滴在多孔材料表面的3种不同动态润湿模式,发现了液滴在微气流作用下的类超疏水悬浮状态.在此基础上,针对具有典型意义的液滴完整浸润模式,结合对多孔材料表面液滴受力模式与受力机理的分析,探讨了不同微气流条件下液滴表观接触角、体积以及底部润湿面积等动态润湿参数与润湿时间之间的依变规律.The dynamic wetting behavior characteristic of droplets is of significant importance in various industrial applications and high technologies,such as surface self-cleaning,surface drag reduction,anti-frosting,and droplet directional transportation.The modifications of coating surface energy and micro/nano structures on substrate surfaces are the conventional and indirect ways to manipulate the droplet dynamic wetting behavior.At present,many direct and external incentive ways,like substrate vibration,electrowetting and additional magnetic field,also have been proposed to control the droplet dynamic wetting behavior.In the present study,inspired from the phenomenon of droplet floating in the air without gravity,an innovative manipulation method had been proposed,which utilized the additional micro-airflow field as a momentum field to control the force distribution and wetting characteristic of droplets.The core idea of this innovative manipulation method was similar as the Leidenfrost phenomenon,which used the gas buoyancy to counter the droplet gravity effect.A porous substrate sintered by copper particles was used as the experimental sample,a micro-airflow field was located at the down side of porous substrate,and a droplet was wetted on the up side of porous substrate.The magnitude of upright momentum force could be changed by adjusting the pressure of micro-airflow field.Under different pressure of micro-airflow field,the dynamic wetting behaviors of droplets on porous substrate were visualized,and the change regulations of dynamic wetting parameters as a function of wetting time were analyzed.According to the results,three different dynamic wetting modes of droplets on the surface of porous materials with micro-airflow were identified,namely,intact infiltration mode,broken infiltration mode and non-infiltration mode.In the intact infiltration mode and broken infiltration mode,the droplets were finally in the state of complete infiltration,while in the non-infiltration mode,the droplets always maintained the s

关 键 词：微气流 多孔表面 动态润湿模式 润湿参数 

分 类 号：O552.42[理学—热学与物质分子运动论]