CIESC Journal ›› 2021, Vol. 72 ›› Issue (10): 5142-5149.DOI: 10.11949/0438-1157.20210498

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Characterizing the temperature profile near contact lines of an evaporating sessile drop

Chengzhi HUANG1(),Haibo TANG1,Tian GU1,Yugang ZHAO1,2()   

  1. 1.Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
    2.Key Laboratory of Icing and Anti/De-icing, China Aerodynamics Research and Development Center, Mianyang 621000, Sichuan, China
  • Received:2021-04-13 Revised:2021-06-24 Online:2021-10-05 Published:2021-10-05
  • Contact: Yugang ZHAO

热敏荧光法用于蒸发液滴近接触线的温度测量

黄承志1(),汤海波1,顾恬1,赵玉刚1,2()   

  1. 1.上海理工大学能源与动力工程学院,上海市动力工程多相流与传热重点实验室,上海 200093
    2.中国空气动力研究与 发展中心结冰与防除冰重点实验室,四川 绵阳 621000
  • 通讯作者: 赵玉刚
  • 作者简介:黄承志(1992—),男,硕士研究生,1642199699@qq.com
  • 基金资助:
    钱学森空间技术实验室太空探索实验培育项目(TKTSPY-2020-01-01);结冰与防除冰重点实验室开放课题(IADL20200103);上海市高校教特聘教授(东方学者)岗位计划项目

Abstract:

Exploring the kinetic principle of static droplet evaporation plays an important role in many related industrial applications. Despite that this phenomenon has been extensively studied over recent decades, an unsolved problem is that how exactly the temperature changes in the adjacent of contact lines. We report in this work a direct experimental measurement revealing the temperature profile of the free interface near contact lines of a sessile drop during the evaporation stage with pinned contact lines. We adapted a microscopic fluorescence-based thermometry, and found that the temperature at the free interface changes drastically near contact lines, forming a concentric fringe pattern which evolves over the whole evaporation process. We attribute the formation of such fringe pattern to a combined mechanism comprising of locally enhanced evaporative cooling near drop edges and a set of thermobuoyancy-driven convective rolls. The new fundamental understanding provided in this work reveals insights into the evaporation dynamics, promising advances in various applications of heat transfer systems.

Key words: fluorescence drop, evaporation, cooling ring, temperature measurement, convection, heat transfer

摘要:

探究静置液滴蒸发的动力学原理在众多的相关工业应用中举足轻重。在过去的数十年间,尽管相关领域的学者进行了大量的研究工作,但仍有一个关键的问题尚未解决,即液滴接触线附近的温度在蒸发过程中到底是如何变化的。通过直接测量的实验方法,报道了液滴在接触线固定不动的蒸发阶段,其接触线附近温度的详细变化过程。利用显微热敏荧光测温技术,其结果表明:液滴接触线附近自由界面的温度将沿径向发生急剧变化,并伴随一组在蒸发过程中不断发生演变的荧光同心圆环,这种荧光条纹带是由于液滴边缘的几何差异性所导致的局部强化蒸发冷却与一组热浮力驱动的对流辊相互作用产生的结果。本研究将为蒸发动力学提供新的认识,并有望在各种对传热系统的应用领域中促成新的进展。

关键词: 荧光液滴, 蒸发, 冷却环, 温度测量, 对流, 传热

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