化工学报 ›› 2016, Vol. 67 ›› Issue (4): 1193-1199.DOI: 10.11949/j.issn.0438-1157.20151122

• 流体力学与传递现象 • 上一篇    下一篇

湿工况下泡沫金属内换热和压降的数值模拟和实验验证

翁晓敏, 高扬, 许旭东, 庄大伟, 胡海涛, 丁国良   

  1. 上海交通大学制冷与低温工程研究所, 上海 200240
  • 收稿日期:2015-07-13 修回日期:2015-08-26 出版日期:2016-04-05 发布日期:2016-04-05
  • 通讯作者: 胡海涛
  • 基金资助:

    国家自然科学基金项目(51576122);上海市自然科学基金项目(15ZR1422000)。

Numerical simulation and experimental validation of heat transfer and pressure drop characteristics in metal foam under wet conditions

WENG Xiaomin, GAO Yang, XU Xudong, ZHUANG Dawei, HU Haitao, DING Guoliang   

  1. Institute of Refrigeration and Cryogenics Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2015-07-13 Revised:2015-08-26 Online:2016-04-05 Published:2016-04-05
  • Supported by:

    supported by the National Natural Science Foundation of China(51576122) and the Natural Science Foundation of Shanghai (15ZR1422000).

摘要:

泡沫金属应用到换热器空气侧有望提高析湿工况下的换热性能。为了了解湿空气在泡沫金属内的热质传递和压降特性,建立了泡沫金属内液滴形成、生长和运动特性的数值模型。基于液滴成核数目和成核临界半径得出液滴形成过程的传质率模型;通过建立液滴与湿空气相界面附近湿空气中水蒸气的组分守恒方程,得出液滴生长过程的传质率模型;通过对不同孔棱柱表面液滴的受力分析,建立在重力和风力的共同作用下的液滴接触角模型。将液滴形成及生长的传质率模型和接触角模型分别作为质量源项和表面张力源项,加入连续性方程、动量方程和能量方程组中,实现对泡沫金属内液滴生长、形成和运动过程模拟。模型的实验验证结果表明,换热量预测值与实验结果的最大偏差为11.9%,压降预测值与实验结果的最大偏差为17.7%。

关键词: 泡沫金属, 湿工况, 传热, 数值模型, 实验验证

Abstract:

The application of metal foam in the airside of heat exchanger has the potential to improve the heat transfer performance under wet conditions. In order to know the heat, mass transfer and pressure drop characteristics of wet air in metal foam, numerical models for water droplet formation, growth and movement are developed. The mass transfer rate model for droplet formation is based on the heterogeneous nucleation rate and critical nucleation radius of droplet; the mass transfer rate model for droplet growth is based on the species conservation of water vapor on phase interface between the droplet and moist air; the contact angle model of the droplet under combined effects of gravity and air forces is based on the force analysis of droplets on the ligament. The models of mass transfer rate during water droplet formation and growth processes and the model of contact angle are reflected in the continuity, momentum and energy conservation equations as the mass source term and momentum term, which realizes the simulation for the water droplet formation, growth and movement processes in metal foam. The experimental validation of the proposed model shows that, the maximum deviations of the heat transfer rate and pressure drop between the simulation results and experimental data are 11.9% and 17.7%, respectively.

Key words: metal foam, wet condition, heat transfer, numerical model, experimental validation

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