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首页> 外文期刊>International Journal of Heat and Mass Transfer >Experimental and numerical study of convective heat transfer and fluid flow in twisted oval tubes
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Experimental and numerical study of convective heat transfer and fluid flow in twisted oval tubes

机译：椭圆管内对流换热和流体流动的实验和数值研究

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摘要

Twisted oval tube heat exchanger is a type of heat exchanger aims at decreasing the pressure drop of the shell side. In the present study, heat transfer and pressure drop performances of twisted oval tube have been studied experimentally and numerically. The experimental study of the twisted oval tube shows that heat transfer process can be enhanced but also with an increasing of pressure drop when compared with the smooth round tube. The effects of geometrical parameters on the performance of the twisted oval tube have been analyzed numerically. The result reveals that the heat transfer coefficient and friction factor both increase with the increasing of axis ratio a/b, while both decrease with the increasing of twist pitch length P. The influence of a/b and P on the overall performance of the twisted oval tubes are also studied. Aiming at obtaining the heat transfer enhancement mechanism of the twisted oval tube, secondary flow, total velocity and temperature distributions of flow section are given. From the analysis it can be concluded that the emergence of twist in the twisted oval tube results in secondary flow. It exists in the form of spiral flow when a/b is big, but in the form of up and down when a/b is small. It is this secondary flow that changes the total velocity and temperature distributions of the twisted oval tube when compared with a smooth oval tube with the same sectional geometric parameters. Then the synergy angle between velocity vector and temperature gradient is reduced and the heat transfer process is enhanced.
机译：扭曲椭圆管式换热器是一种旨在减小壳体侧压降的换热器。在本研究中，已经通过实验和数值研究了扭曲椭圆管的传热和压降性能。椭圆形扭曲管的实验研究表明，与光滑的圆形管相比，传热过程既可以增强传热过程，又可以降低压降。数值分析了几何参数对椭圆形扭曲管性能的影响。结果表明，传热系数和摩擦系数均随着轴比a / b的增加而增加，而均随着扭曲节距长度P的增加而降低。a / b和P对扭曲整体性能的影响还研究了椭圆形管。为了获得扭转椭圆管传热的机理，给出了二次流动，总速度和流动截面的温度分布。从分析中可以得出结论，在扭曲的椭圆形管中出现扭曲会导致二次流动。当a / b大时，它以螺旋流的形式存在，但是当a / b小时，它以上下的形式存在。与具有相同截面几何参数的光滑椭圆管相比，正是这种次级流动改变了扭曲椭圆管的总速度和温度分布。然后减小了速度矢量和温度梯度之间的协同角，并增强了传热过程。

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  • 来源
    《International Journal of Heat and Mass Transfer》 |2012年第18期|p.4701-4710|共10页
  • 作者

    Xiang-hui Tan; Dong-sheng Zhu; Guo-yan Zhou; Li-ding Zeng;

  • 作者单位

    Key Laboratory of Pressure Systems and Safety of Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, PR China;

    Key Laboratory of Pressure Systems and Safety of Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, PR China;

    Key Laboratory of Pressure Systems and Safety of Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, PR China;

    Key Laboratory of Pressure Systems and Safety of Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, PR China;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    twisted oval tube; heat transfer performance; pressure drop performance; heat transfer enhancement mechanism;

    机译：椭圆形扭曲管;传热性能;压降性能;传热增强机理;

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