电场对竖直微槽润湿及毛细流动特性影响  

Electric field effect on wetting and capillary flow characteristics in vertical microgrooves

作　　者：董宜放 于樱迎 胡学功[2,4] 裴刚 DONG Yifang;YU Yingying;HU Xuegong;PEI Gang(Department of Thermal Science and Energy Engineering,University of Science and Technology of China,Hefei 230027,Anhui,China;Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China;Nanjing Institute of Future Energy System,Nanjing 211135,Jiangsu,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学技术大学热科学和能源工程系,安徽合肥230027 [2]中国科学院工程热物理研究所,北京100190 [3]中科南京未来能源系统研究院,江苏南京211135 [4]中国科学院大学,北京100049

出　　处：《化工学报》2022年第7期2952-2961,共10页CIESC Journal

基　　金：国家重点研发计划项目(2017YFB0403200)。

摘　　要：竖直微槽群毛细结构广泛应用在重力热管、蒸发器等散热设备内,但受重力等因素影响易达到毛细极限。引入电场的主动强化方式来提高竖直微槽的毛细极限,并通过实验和建立数学模型研究电场对竖直微槽内液体润湿及毛细流动特性的影响。结果表明,电场可以提高竖直微槽内液体润湿高度,当电场为5.0 kV时与无电场时相比,润湿高度强化比可达到30.0%。同时,电场作用下流体在微槽道内的毛细润湿流动呈分段效应:润湿流动初期,润湿高度与时间的1/2次方呈线性关系,即h-t^(1/2),润湿速率与润湿高度的倒数呈线性关系,即v-1/h;润湿流动中后期,润湿高度与时间的1/3次方呈线性关系,即h-t^(1/3),润湿速率与润湿高度平方的倒数呈线性关系,即v-1/h^(2),且润湿速率随时间呈下降趋势。Vertical microgroove capillary structures are widely used in heat transfer devices such as gravity heat pipes,evaporator and other heat transfer devices.The capillary rise in microgrooves attracts increasing attentions since it affects capillary limit significantly,which is easy to be reached due to the structure,gravity and other factors,and has a great influence on the heat transfer performance of the heat pipes.Thus,to improve the capillary limit of the vertical microgrooves,electric field,as one of the active enhanced technology,is introduced to the experiment system.The influence of the electric field on the wetting and capillary flow characteristics of the liquid in the vertical microgroove is studied experimentally and a mathematical model is established to understand the wetting and flow mechanisms of liquid in the vertical microgrooves under the action of electric field.The results show that the electric field can improve the wetting height of the liquid in the vertical microgrooves.When the electric field is 5.0 kV,the wetting height enhancement ratio can reach 30.0%compared with no electric field.Besides,the liquid wetting and capillary flow in the microgrooves under electric field are segmented:at the beginning of the capillary wetting flow,the square of the wetting height is linearly related to time,that is,h-t^(1/2),and at the long-term of the wetting flow,the wetting height is linearly related to the 1/3 power of time,that is,h-t^(1/3).Besides,the relationship between the wetting velocity and the wetting height first follows v-1/h,then is governed by v-1/h^(2).Moreover,the wetting velocity decreases with time.

关 键 词：微通道 流动 数学模型 电场 润湿高度 润湿速率 

分 类 号：TQ021.1[化学工程]