化工进展 ›› 2020, Vol. 39 ›› Issue (8): 2989-2997.DOI: 10.16085/j.issn.1000-6613.2019-1778

• 化工过程与装备 • 上一篇    下一篇

全氟烷基表面活性剂强化池沸腾换热

邢美波(), 龚志明, 王瑞祥   

  1. 北京建筑大学环境与能源工程学院,北京市建筑能源高校综合利用工程技术研究中心,北京 100044
  • 出版日期:2020-08-01 发布日期:2020-08-12
  • 通讯作者: 邢美波
  • 作者简介:邢美波(1987—)女,博士,副教授,研究方向为强化传热及能源的高效利用。E-mail:xingmeibo@bucea.edu.cn
  • 基金资助:
    国家自然科学基金(51906013);北京市教委科技计划(KM201910016010)

Nucleate pool boiling heat transfer characteristics of perfluoroalkyl quaternary ammonium iodide

Meibo XING(), Zhiming GONG, Ruixiang WANG   

  1. Beijing Engineering Research Center of Sustainable Energy and Buildings, School of Environment and Energy Engineering, Beijing University of Civil Engineering and Architecture, Beijing 100044, China
  • Online:2020-08-01 Published:2020-08-12
  • Contact: Meibo XING

摘要:

针对不同浓度的全氟烷基碘化物(Le-134)水溶液进行了核态池沸腾换热实验研究。首先对Le-134的界面吸附特性及在紫铜表面的润湿性进行了研究。结果表明,其静态表面张力随浓度增大而减小,动态表面张力下降速度随浓度增加而加快,在超过临界胶束浓度(critical micelle concentration,CMC)的较高浓度下(≥40mg/L),10s以内溶液表面张力即降低到20mN/m以下。Le-134水溶液在紫铜表面接触角随浓度增加而减小,在300mg/L时接触角仅为21°,具有良好的润湿性。沸腾过程与去离子水相比,Le-134水溶液产生的汽泡数量明显增多,汽泡尺寸减小,汽泡合并现象减少。结果表明,Le-134的添加可以有效强化池沸腾换热,同热流密度下随浓度增大强化效果越显著;同浓度下,随热流密度增大强化效果有所减弱。在10W/cm2下,300mg/L的Le-134相对去离子水工况强化效果最明显,沸腾表面过热度减少49.3%,沸腾换热系数增加109.1%。

关键词: 表面活性剂, 沸腾传热, 汽泡动力学, 界面特性

Abstract:

Saturated pool boiling heat transfer experiments for different concentrations of perfluoroalkyl iodide (Le-134) aqueous solution has been experimentally investigated. The interface adsorption characteristics of Le-134 and the wettability of copper surface were investigated firstly. The static surface tension decreased with increasing concentration, and the variation of dynamic surface tension reduction increased with increasing concentration. At the concentration exceeding CMC (≥40mg/L), the surface tension of the solution was reduced to less than 20mN/m within 10s. Le-134 solution had good wettability, and the contact angle of the aqueous solution on the surface of the copper decreased with increasing concentration, which was only 21° at 300mg/L. Compared with deionized water, the amount of bubbles produced by Le-134 aqueous solution in pool boiling was significantly increased besides the bubble size and the bubble coalescence was reduced. It can be demonstrated that the heat transfer enhancement was more effective with the increase of concentration at the same heat flux, while the heat transfer performance was weakened with the increase of heat flux at the same concentration. Compared to deionized water, the obvious enhancement was observed at 10W/cm2 with 300mg/L Le-134. The superheat of the boiling surface was reduced by 49.3%, and the boiling heat transfer coefficient was increased by 109.1%.

Key words: surfactants, pool boiling heat transfer, bubble kinetics, interface characteristic

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