CIESC Journal ›› 2022, Vol. 73 ›› Issue (7): 2952-2961.DOI: 10.11949/0438-1157.20220427

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

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

Yifang DONG1,2,3(),Yingying YU2,3,Xuegong HU2,4(),Gang PEI1   

  1. 1.Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, Anhui, China
    2.Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
    3.Nanjing Institute of Future Energy System, Nanjing 211135, Jiangsu, China
    4.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-03-25 Revised:2022-05-14 Online:2022-08-01 Published:2022-07-05
  • Contact: Xuegong HU

电场对竖直微槽润湿及毛细流动特性影响

董宜放1,2,3(),于樱迎2,3,胡学功2,4(),裴刚1   

  1. 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
  • 通讯作者: 胡学功
  • 作者简介:董宜放(1989—),男,博士研究生,dongyifang@iet.cn
  • 基金资助:
    国家重点研发计划项目(2017YFB0403200)

Abstract:

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-t1/2, 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-t1/3. Besides, the relationship between the wetting velocity and the wetting height first follows v-1/h, then is governed by v-1/h2. Moreover, the wetting velocity decreases with time.

Key words: microchannels, flow, mathematical modeling, electric field, wetting height, wetting velocity

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-t1/2,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-t1/3,润湿速率与润湿高度平方的倒数呈线性关系,即v-1/h2,且润湿速率随时间呈下降趋势。

关键词: 微通道, 流动, 数学模型, 电场, 润湿高度, 润湿速率

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