Theoretical analysis of wetting characteristics in rectangular microgrooves under electric field

doi:10.11949/j.issn.0438-1157.20180523

Abstract

Abstract:

A one dimensional semi analysis model was developed based on accommodation theory to study the effect of electric field on liquid wetting characteristics in vertical rectangular capillary microgrooves heat sinks. The effects of electric field intensity, heat flux and microgrooves dimensions on liquid wetting characteristics are investigated. The results show that the electric field can be utilized to improve the wetting length of liquid in microgrooves heat sinks. The wetting length decreases with heat flux under the electric field effect. When the heat flux is relatively small, the enhancement of the wetting length due to the electric field intensity is higher, yet the enhancement due to the electric field decreases with the heat flux. The accommodation length and the corner flow length under the action of electric field are studied and compared. Both the accommodation length and the corner flow length increase with the increasing electric field intensity yet the enhancement in corner flow length is more distinguished. Since the liquid film in the corner flow stage is thinner than the accommodation stage, according to thin film theory, the enhancement of the corner flow length is important to the heat transfer enhancement of the rectangular microgrooves. Effects of microgroove dimensions on wetting length under electric field effect are considered. The length of wetting under the action of electric field increases and decreases with the increase of groove depth and groove width. Compared with microgrooves with smaller depth and width, when the groove size is larger, the electric field strength is more significant for with the liquid wetting strengthening in the microgrooves.

Key words: microchannels, heat transfer, numerical analysis, electric field, rectangular microgrooves heat sink, wetting length

摘要：

以预测电场作用下竖直矩形微槽群热沉内液体润湿特性为目的，基于自适应理论，建立一维轴向模型，研究了电场强度、热通量以及微槽尺寸对润湿特性的影响。结果表明：电场作用下润湿长度随热通量增加逐渐降低。当热通量较低时，电场强度对润湿长度的强化较大，但随着热通量的增大强化程度减弱。电场强度对矩形微槽群热沉适应长度的强化较小，而对于边角流动区域长度的强化较为显著。电场作用下润湿长度随槽深和槽宽的增加分别呈增加和下降的趋势。与较小槽深槽宽相比，当槽尺寸较大时，电场强度对微槽内液体润湿强化更为显著。

关键词: 微通道, 传热, 数值分析, 电场, 矩形微槽群热沉, 润湿长度

CLC Number:

TQ021.3

YU Yingying, TANG Jinchen, HU Xuegong. Theoretical analysis of wetting characteristics in rectangular microgrooves under electric field[J]. CIESC Journal, 2018, 69(10): 4216-4223.

于樱迎, 唐瑾晨, 胡学功. 电场作用下矩形微槽群润湿特性数值分析[J]. 化工学报, 2018, 69(10): 4216-4223.

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