| 降膜蒸发过程熵产分析 |
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| 引用本文： | 陈曦,汪建军,朱家骅,帅剑云,冯昭华. 降膜蒸发过程熵产分析[J]. 化工学报, 2006, 57(7): 1518-1524 |
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| 作者姓名： | 陈曦 汪建军 朱家骅 帅剑云 冯昭华 |
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| 作者单位： | 四川大学化学工程学院,四川,成都,610065;福建省环境科学与工程研究设计院,福建,福州,350004 |
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| 基金项目： | 高比容电子铝箔的研究开发与应用项目 , 国家高技术研究发展计划(863计划) |
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| 摘 要： | 从热力学第二定律出发，将普适体系的熵产表达推广于降膜蒸发过程熵产分析并得到熵产计算式.引入单位熵产数并得到Reynolds数大于1450(cpμ/λ)-1.06(0.5-0.25ω)-1情况下和Reynolds数之间的定量关系，据此揭示了降膜蒸发过程熵产随降膜管内液膜厚度减小先降低再增大的规律，对应存在最小熵产数.与φ30×2×6000传热管内磷酸降膜蒸发实验数据对比结果吻合良好，表明本文熵产计算式可以根据过程的热力参数表达降膜蒸发过程的熵产规律，对过程强化和提高热力学效率具有实际指导意义.
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| 关 键 词： | 降膜蒸发 熵产 单位熵产数 最小熵产分析 |
| 文章编号： | 0438-1157（2006）07-1518-07 |
| 收稿时间： | 2005-11-07 |
| 修稿时间： | 2005-11-072006-03-30 |
Analysis of entropy generation in falling film evaporation |
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| CHEN Xi,WANG Jianjun,ZHU Jiahua,SHUAI Jianyun,FENG Zhaohua. Analysis of entropy generation in falling film evaporation[J]. Journal of Chemical Industry and Engineering(China), 2006, 57(7): 1518-1524 |
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| Authors: | CHEN Xi WANG Jianjun ZHU Jiahua SHUAI Jianyun FENG Zhaohua |
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| Abstract: | Based on the second law of thermodynamics for an open system under non-equilibrium state an intensive analysis of the entropy generation in the process of falling film evaporation was made.A quantitative correlation was deduced to calculate the unit entropy generation number,Ns from the traditional Reynolds number and other parameters under the condition of Re>1450(cpμ/λ)-1.06(0.5-0.25ω)-1.It was unveiled that Ns decreased with decreasing thickness of the falling film and increased after the optimal ω, which corresponded with a minimum value of Ns.The good agreement between the expressions of correlation and the results obtained from an experimental rig of falling film evaporation for phosphoric acid concentration in a vertical heated tube with the dimension of φ30×2×6000 demonstrated that the correlation equation could be rationally used to predict the entropy generation in falling film evaporation.This theoretical prediction, calculated from ordinary thermal process parameters is useful in enhancement of thermodynamic efficiency in industrial processes. |
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| Keywords: | falling film evaporation entropy generation unit entropy generation number minimization analysis of entropy generation |
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