储能科学与技术 ›› 2020, Vol. 9 ›› Issue (6): 1798-1805.doi: 10.19799/j.cnki.2095-4239.2020.0138

• 储能材料与器件 • 上一篇    下一篇

基于LBM的三角腔固液相变模拟

高一倩1,2(), 柳　毅1,2, 李　凌1,2()   

  1. 1.上海理工大学能源与动力工程学院
    2.上海市动力工程多相流与传热重点实验室，上海 200093
  • 收稿日期:2020-04-06 修回日期:2020-04-27 出版日期:2020-11-05 发布日期:2020-10-28
  • 通讯作者: 李　凌 E-mail:2995984189@qq.com;liling@usst.edu.cn
  • 作者简介:高一倩（1993—），女，硕士研究生，主要从事相变蓄热方面的研究，E-mail:2995984189@qq.com；
  • 基金资助:
    国家自然科学基金项目(51476102)

Numerical simulation of natural convection melting inside a triangular cavity using Lattice Boltzmann method

Yiqian GAO1,2(), Yi LIU1,2, Ling LI1,2()   

  1. 1.School of Energy and Power Engineering, University of Shanghai for Science and Technology
    2.Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering, Shanghai 200093, China
  • Received:2020-04-06 Revised:2020-04-27 Online:2020-11-05 Published:2020-10-28
  • Contact: Ling LI E-mail:2995984189@qq.com;liling@usst.edu.cn

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摘要：

利用格子Boltzmann方法(LBM)模拟三角腔中的自然对流融化现象，分析瑞利数Ra、局部热源尺寸L及位置S对其相变换热和储能特性的影响。数值计算表明：①相变材料在全热边界三角腔内的完全融化时间随对流循环强度的增加呈现先增后减的趋势，临界Ra值为31000，当Ra大于31000时，融化进程和对流效应呈现正相关，低于31000时，表现为负相关；②局部加热尺寸L较小时，中间热源的融化时间最短，储能效率更高；上部热源的融化时间最长。此外，因受冷斜壁的影响程度不同，随着对流效应的增强，上部热源的总融化时间增大，下部热源的总融化时间缩短，而中间热源的总融化时间随对流强度的增加呈先增后减的趋势，存在一临界值Ra=19000；③L≥0.5时，下部加热成为最佳融化位置，储能时间最短；随着对流强度的增加，上、中、下三种局部加热方案的总融化时间均表现为先增后减的趋势，且临界Ra值随着加热长度的增加而增加，此外，加热尺寸在不同位置上的变化对相变储能进程也有不同的影响。本研究工作有助于为实际相变换热设备的优化设计和高效储能提供理论依据和技术指导。

关键词: 格子Boltzmann方法, 相变储能, 自然对流融化过程, 三角腔

Abstract:

The Lattice Boltzmann method is used to simulate the natural convective melting in a triangular cavity. The effects of the Rayleigh number Ra, local heat source size L, and location S on its phase change heat transfer and energy storage characteristics are analyzed. The numerical results show that the full melting time in the triangular cavity with a full thermal boundary initially increases then decreases with the increase of the convective strength. The inflection point is at 31000. The melting process and the convective effect show a positive correlation when Ra > 31000. In contrast, a negative correlation is observed when Ra < 31000. Moreover, when the local heating size L is small, the melting time of the middle heat source is the shortest, and the energy storage efficiency is the highest. The melting time of the uppermost heat source is the longest. In addition, due to the different influence of the cold inclined the total melting time of the upper heat source increases with the convective effect enhancement wall. By contrast, the total melting time of the lower heat source shortens, while that of the intermediate heat source first increases then decreases with a critical value of Ra=19000. Meanwhile, when L≥0.5, the lowest heating becomes the best melting position, and the energy storage time is the shortest. As the convective intensity increases, the total melting time of the upper, middle, and lower local heating schemes first increases and then decreases, and the critical Ra values increase with the heating length increase. Furthermore, the change of the heating size in different positions has different effects on the energy storage process. This work will be helpful in providing theoretical basis and technical guidance for the optimal design and efficient energy storage of the actual phase change heat exchange equipment.

Key words: Lattice Boltzmann method, phase change energy storage, natural convection melting process, triangular cavity

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