北京航空航天大学学报 ›› 2018, Vol. 44 ›› Issue (6): 1283-1293.doi: 10.13700/j.bh.1001-5965.2017.0412

• 论文 • 上一篇    下一篇

临近空间环境下封闭方腔内耦合换热特性

字贵才, 贺卫亮   

  1. 北京航空航天大学 宇航学院, 北京 100083
  • 收稿日期:2017-06-19 出版日期:2018-06-20 发布日期:2018-06-28
  • 通讯作者: 贺卫亮.E-mail:heweiliang@buaa.edu.cn E-mail:heweiliang@buaa.edu.cn
  • 作者简介:字贵才 男,硕士研究生。主要研究方向:飞行器设计;贺卫亮 男,博士,教授,博士生导师。主要研究方向:飞行器设计。

Conjugate heat transfer characteristics of enclosure cavity in near space environment

ZI Guicai, HE Weiliang   

  1. School of Astronautics, Beijing University of Aeronautics and Astronautics, Beijing 100083, China
  • Received:2017-06-19 Online:2018-06-20 Published:2018-06-28

摘要: 以临近空间浮空器载荷舱为应用背景,对复杂热边界条件下含热源的三维封闭方腔内自然对流、表面辐射和导热的耦合问题进行了数值模拟。综合考虑对流换热、长波辐射、太阳辐射等因素的影响,建立了临近空间热环境模型。通过Fluent软件用户自定义函数(UDF)引入外部非定常的辐射-对流耦合热边界条件,对腔内换热特性的昼夜变化进行研究,并分析了腔壁厚度、发射率和导热系数对其的影响。数值结果表明,腔内平均温度昼夜变化很小,约为12.9 K,但温度场分布随太阳方位变化而变化;腔内对流换热较弱,同一时刻最大温差约为71.3 K;腔壁热阻和发射率增加会削弱自然对流的强度。

关键词: 临近空间, 封闭方腔, 耦合传热, 自然对流, 数值模拟

Abstract: Aimed at the application of near space aerostats' load cabins, numerical simulation of natural convection, surface thermal radiation and heat conduction in a cubical enclosure cavity with a heat source in complex thermal boundary conditions was carried out. A model of near-space thermal environment was established considering the effects of convective heat transfer, infrared radiation and solar radiation. The diurnal variation of the thermal characteristics in the enclosure cavity was studied by introducing the external unsteady convection-radiation coupling thermal boundary conditions through the Fluent software's user-defined function (UDF). The effects of solid wall thickness, emissivity and thermal conductivity were discussed. The numerical results indicate that the average temperature change in the enclosure cavity is about 12.9 K during one day, and the temperature field distribution changes with the sun's position. The natural convection in the enclosure cavity is weak and the maximum temperature difference is 71.3 K at the same time. Increased thermal resistance and surface emissivity lead to weakening of natural convection in the cavity.

Key words: near space, enclosure cavity, conjugate heat transfer, natural convection, numerical simulation

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