| 摘要: |
| 溴化锂溶液降膜吸收是吸收式空调系统中常见的热质传递形式之一。本文对溶液降膜吸收过程的热质耦合传递分析，建立了溴化锂溶液垂直降膜吸收热质传递的二维数学物理模型，采用CFD-Fluent对模型进行求解。计算得到不同Re下的液膜界面温度、液膜内浓度分布、传热传质通量及传热传质系数等。分析了Re对降膜吸收过程中热质传递的影响。结果表明：当液膜Re＜150时，液膜界面平均温度与平均传质系数随着Re的增大而增大，而平均传热系数随着Re的增大而减少；平均传热传质通量均是随着Re的增大而先增大后减小，存在一个最佳液膜Re使降膜吸收过程的传热传质通量达到最大，即Re=50时，平均传热和传质通量分别达到最大值7.2 kW/m2与2.9×10-3 kg/(m2?s)。 |
| 关键词: 热传质 溴化锂溶液 降膜吸收 雷诺数 |
| DOI： |
| 投稿时间：2017-01-09
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| 基金项目:西安市科技计划项目(CXY1514(2))资助。 |
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| Numerical Study on the Heat and Mass Transfer of LiBr/H2O Falling Film Absorption with Low Reynolds Number |
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Zhang Lianying, Li Yang, Wang Yuan, Yang Xiaohu, Jin Liwen, Meng Xiangzhao
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| (School of Human Settlements and Civil Engineering, Xi’an Jiaotong University) |
| Abstract: |
| LiBr/H2O falling-film absorption is a common heat-and mass-transfer process in an absorption air-conditioning system. By analyzing the coupled heat and mass transfer of the falling-film absorption process, two-dimensional physical and mathematical models of the falling-film absorption along a vertical wall were established. The model was solved using the Fluent computational-fluid-dynamics software. The interfacial temperature, the concentration profile across the falling film, and the average heat-and mass-transfer fluxes and coefficients were obtained. The effect of the Reynolds number on the heat and mass transfer of the falling film was investigated. The results show that, when the film Reynolds number is less than 150, the average interfacial temperature increases with the increasing Reynolds number; however, the rising trend of the average interfacial temperature is more and more gentle. The average mass-transfer coefficient increases with the increasing Reynolds number, while the average heat-transfer coefficient decreases. Simultaneously, with the increasing Reynolds number, the average heat-and mass-transfer fluxes first increase and then decrease. An optimal Reynolds number exists that leads to the maximum heat- and mass-transfer fluxes. The average heat-and mass-transfer fluxes reach their maximums, 7.2 kW/m2 and 2.9×10-3 kg/(m2?s), respectively, when the Reynolds number is 50. |
| Key words: heat and mass transfer lithium bromide solution falling film absorption Reynolds number |
