内置旋流发生器传热管强化传热的研究

论文摘要

在工业领域，效率的微小提高即可带来可观的经济效益。本文通过实验的方式研究了传热管内置螺旋塑料元件的强化传热，该元件可以在水流作用下自动旋转。该内插件由PC制作而成的100个螺旋塑料元件构成，放置在逆流换热器的传热管内以便在传热管内产生旋流而增加传热管的传热速率。传热管内流动速率的雷诺数范围为6600—22000。旋流装置放置在同心套管换热器的内管。冷水在外管流动，而热水在内管中流动。光管进行实验的数据与上述实验得到的数据相比，内置螺旋塑料元件的传热管比光管具有更高的总传热系数和更高的努塞尔数，且努塞尔数提高了大约130％。通过实验方式得到的光管的平均努塞尔数与迪图斯-贝尔特方法的平均努塞尔数相比，误差范围在13.1％-20.8％内。该项技术不仅可以用于换热器的强化传热，还可以换热器用于需要自动清洗污垢的场合。

论文目录

• ABSTRACT
• 摘要
• Chapter 1 Introduction
• 1.1 General
• 1.2 Heat Exchanger
• 1.3 Energy Equations for Heat Exchangers
• 1.4 Log Mean Temperature Differences
• 1.5 The Enhancement Techniques
• 1.5.1 Passive Techniques
• 1.5.2 Active Techniques
• 1.6 Cleaning of Heat Exchanger
• Chapter 2 Literature Review
• 2.1 Introduction
• 2.2 Survey of Previous Work
• 2.2.1 Flow through Internally Finned Tubes
• 2.2.2 Swirl Flow
• 2.2.3 Roughened Surfaces
• 2.2.4 Micro Fins
• 2.2.5 Offset Strip Fins
• 2.2.6 Finned Tubes
• 2.3 Objective of the Present Work
• Chapter 3 Test Section and Calculation Procedure
• 3.1 General Description of the Test Section
• 3.2 Experimental Apparatus and Procedure
• 3.3 Data Reduction Equations
• 3.4 Wilson Plots Analysis
• 3.4.1 Steps of Determination
• Chapter 4 Result and Discussion
• 4.1 Introduction
• 4.2 Effect of Plastic Spiral Element on Overall Heat Transfer Coefficient
• 4.3 Experimental Results of Smooth Tube
• 4.4 Effect of Plastic Spiral Element on Inside Heat Transfer Coefficient
• Chapter 5 Conclusions and Recommendations
• References
• Appendix 1
• Appendix 2
• Acknowledgement
• Paper published
• Biographies of the Supervisor and Author
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