小管径水平圆管管外冷凝传热数值分析Numerical Analysis of Condensation Heat Transfer for Small Diameter Horizontal Circular Tubes
贾利梅;
Jia Limei;School of Mechanical Engineering,Hubei University of Arts and Science;
摘要(Abstract):
设备小型化发展的不断深入和高热流密度换热的需要促使了具备更高换热性能的小管径冷凝换热的研究。基于Nusselt膜状冷凝传热理论,构建了水平圆管从管外冷凝换热直到管内对流换热的计算模型和程序,并借助已有文献的试验结果完成了计算模型和程序的校验。随后,文章重点探讨了水平圆管管外冷凝换热的热阻分布,揭示当前管外冷凝换热热阻在单管整体换热热阻中所占比重较小的事实。通过进一步计算和比较本文认为,管外冷凝换热系数适度的退化对小管径水平圆管的整体换热影响较小,并不能改变小管径管外冷凝换热的优势。本数值分析可为小管径壳管换热器的研制以及微小管径冷凝换热试验的设计提供理论支撑。
The further development of device miniaturization and the requirement of high heat flux heat transfer have been promoting researches into condensation of mini tubes that possess better heat transfer performance.Based on the theory of Nusselt's filmwise condensation heat transfer,a calculation model as well as the corresponding program for the heat transfer of horizontal circular tubes was established,which involves from the condensation heat transfer outside the tube to the heat convection inside the tube.The model and the program were verified by the experimental results of the existing literature.Subsequently,the distribution of the thermal resistance of the condensation heat transfer outside the horizontal circular tube was discussed,and the fact that the thermal resistance of the condensation heat transfer accounts for a small proportion in the overall heat transfer resistance for a single tube was revealed.Through further calculation and comparison,it was concluded that a moderate degradation of the condensation heat transfer coefficient outside a tube has little effect on the overall heat transfer for a horizontal circular tube with small diameter,and it cannot change the heat transfer advantages of the horizontal circular tube with small diameter.This study can provide theoretical support for the development of shell and tube heat exchanger with tubes of small diameter and the design of condensation heat transfer experiments with mini tubes.
关键词(KeyWords):
膜状冷凝;小管径;水平圆管;换热;热阻
filmwise condensation;small diameter;horizontal circular tube;heat transfer;thermal resistance
基金项目(Foundation): 湖北省技术创新专项(软科学研究项目:2018ADC077);; 教育部人文社会科学研究青年基金项目(17YJC630084)
作者(Authors):
贾利梅;
Jia Limei;School of Mechanical Engineering,Hubei University of Arts and Science;
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- 膜状冷凝
- 小管径
- 水平圆管
- 换热
- 热阻
filmwise condensation - small diameter
- horizontal circular tube
- heat transfer
- thermal resistance