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Numerical simulation of boiling heat and mass transfer in the tube for MVR evaporator

ZHANG Lin,GAO Lili,CUI Lei,ZHAO Qingliang   

  1. School of Mechanical Engineering,Changzhou University,Changzhou 213016,Jiangsu,China
  • Online:2013-03-05 Published:2013-03-05

classifier;hierarchical process;numerical simulation;unsteady

张 琳,高丽丽,崔 磊,赵庆良   

  1. 常州大学机械工程学院,江苏 常州 213016

Abstract: A three-dimensional physical model of boiling heat and mass transfer in the tube for MVR rising film circulation evaporator was built by CFD software. Standard k-ε turbulent model,multiphase mixture model and user-defined function (UFD) of the mass transfer and energy transfer between vapor phase and liquid phase compiled by C language were used in the simulation of the performances of boiling evaporation heat and mass transfer of amino acid waste water in the smooth tube and corrugated tube. The distribution laws of the turbulent characteristic field,temperature field,phase change volume fraction and average boiling heat transfer coefficient of smooth tube and corrugated tube were obtained. The flow and the heat and mass transfer characteristic of smooth tube and corrugated tube were compared. The influences of different wall heating temperature and inlet velocity on boiling heat transfer performance were analyzed. The results showed that the boiling evaporation operation of amino acid waste water in low temperature and negative pressure conditions can be realized by MVR rising film circulating evaporator,the different structures of heat transfer tube influence the fluid flow and heat and mass transfer,corrugated tube can improve the average boiling heat transfer coefficient 2.2 times of smooth tube.

Key words: MVR evaporator;boiling evaporation;enhancement heat and mass transfer, numerical simulation;saving energy

摘要: 建立了MVR升膜循环蒸发器管内沸腾蒸发传热传质三维物理模型,采用标准k-ε湍流模型、多相流混合模型和C语言编写气液两相之间质量传递和能量传递的自定义函数,对光管和波纹管内氨基酸废水溶液的沸腾蒸发传热传质特性进行了数值模拟研究,得到了光管和波纹管内湍流强度、温度场、相变含气率和平均沸腾传热系数的分布规律,比较了光管和波纹管内流体的流动和传热传质特性,分析了不同管壁加热温度和进口流速对沸腾传热性能的影响。结果表明,采用MVR升膜循环蒸发器可以实现氨基酸废水溶液的低温负压沸腾蒸发操作,传热管的结构对流体的流动和传热传质有影响,波纹管与光管相比可使平均沸腾传热系数提高2.2倍。

关键词: MVR蒸发器, 沸腾蒸发, 强化传热传质, 数值模拟, 节能

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