化工进展 ›› 2019, Vol. 38 ›› Issue (01): 14-29.DOI: 10.16085/j.issn.1000-6613.2018-1133

• 化工过程与装备 • 上一篇    下一篇

常/微重力下微结构表面强化沸腾换热研究进展

魏进家1,2(),刘斌1,张永海1   

  1. 1. 西安交通大学化学工程与技术学院,陕西 西安 710049
    2. 西安交通大学动力工程多相流国家重点实验室,陕西 西安 710049
  • 收稿日期:2018-05-31 修回日期:2018-07-24 出版日期:2019-01-05 发布日期:2019-01-05
  • 作者简介:魏进家(1971—),男,博士,教授,博士生导师,研究方向为多相流与传热。E-mail:<email>jjwei@mail.xjtu.edu.cn</email>。
  • 基金资助:
    国家自然科学基金(51636006,51611130060,51506169);国家自然科学基金(51636006,51611130060,51506169)。

Jinjia WEI1,2(),Bin LIU1,Yonghai ZHANG1   

  1. 1. School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
    2. State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
  • Received:2018-05-31 Revised:2018-07-24 Online:2019-01-05 Published:2019-01-05

摘要:

表面改性是提高沸腾换热性能的重要手段。本文以自主开发的微结构表面为基础,简述了近三年来常重力条件下的微/纳结构表面强化池沸腾换热、临界热流密度预测模型及经验关联、微重力条件下(重力水平为10-2~10-3 g 0g 0=9.8m/s2)加热面尺寸对沸腾换热的影响和气泡动力学等方面的研究进展。对柱状微结构参数和排布方式进行优化后的多尺度复合微结构表面相比柱状微结构表面和光滑表面,其壁面温度可分别降低8K和30K以上,而临界热流密度(CHF)则分别提高了28%和119%以上。体积分数为0.02%的乙醇/银纳米流体相对于单纯的乙醇工质,相同条件下换热壁面温度可降低8~15K,而机械作用对CHF约有25%的提高。通过对柱状微结构的几何参数以及临界发生时的供液机理研究,建立了考虑柱状微结构参数的CHF关联式、微/纳结构表面考虑液体毛细芯吸作用的CHF预测模型以及考虑液体铺展速度的CHF预测关联式。根据微重力下加热面尺寸对沸腾的影响的研究,提出了基于恒定热流密度的换热预测关联式。考虑微重力条件下主气泡和小气泡的表面张力,对传统的气泡脱离直径预测的力平衡模型进行了改进,进一步提高了微重力下气泡的脱离半径的预测精度。此外,对近年来以FC-72为工质的其他强化池沸腾换热微结构表面的研究成果进行了总结,并与自主研发的微结构表面换热性能进行了对比与分析,为今后的研究方向和应用指出了方向。

关键词: 微结构, 纳米结构, 多尺度, 传热, 池沸腾, 微重力, 气泡动力学

Abstract:

Surface modification is an important approach to enhance boiling heat transfer. Based on the self-developed microstructure surface,this study reviewed the progress in boiling heat transfer over microstructured surfaces in the past three years,including the enhanced pool boiling heat transfer over micro/nanostructured surfaces in normal gravity,model and empirical correlations for CHF (critical heat flux) prediction,and effect of heater size on pool boiling heat as well as bubble dynamics under microgravity conditions (the microgravity level is 10-2—10-3 g 0g 0=9.8m/s2). Compared to micro-pin-fins surfaces and smooth surface, the wall superheat of the bi-structured surface which achieved the best heat transfer performance was reduced by more than 8K and 30K respectively, and the CHF was increased by 28% and 119% respectively. The wall superheat of the alcohol/silver nanofluid with a volume fraction of 0.02% was found decreased by 8—15K under the same conditions compared with the pure ethanol fluid,and the CHF can be increased by about 25% with vibration and agitation. The CHF prediction model of microstructured surfaces considering the liquid capillary effect,and the CHF prediction correlations,which consider the geometric parameters of micro-pin-fins and liquid spreading velocity, respectively, were established by studying the effects of the geometric parameters of micro-pin-fins and the fluid supply mechanism on CHF. Based on the results of the influence of the heater size on boiling heat transfer in microgravity,the heat transfer prediction correlation based on constant heat flux was proposed. Considering the interaction between the primary bubble and the small bubble in microgravity, a modified model of bubble diameter was developed and it can predict the bubble departure diameter at medium and high heat fluxes more accurately. Meanwhile,the pool boiling heat transfer data from other enhancement techniques were compared each other. The advantages and shortcomings of various enhanced boiling heat transfer structures were summarizes and analyzed,and the future prospect of boiling heat transfer enhancement was suggested. This review can provide more information for the further study and industrial application.

Key words: microstructure, nanostructure, multiscale, heat transfer, pool boiling, microgravity, bubble dynamics

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