重庆理工大学学报(自然科学) ›› 2023, Vol. 37 ›› Issue (4): 339-347.

• “第 23届流体动力与机电控制工程国际学术会议”专栏 • 上一篇    下一篇

受二次流涡流影响的螺旋盘管内传热特性研究

华 珍,王效岳   

  1. (1.山东理工大学 交通与车辆工程学院,山东 淄博 255000; 2.山东理工大学 机械工程学院,山东 淄博 255000)
  • 出版日期:2023-05-06 发布日期:2023-05-06
  • 作者简介:华珍,女,正高级实验师,主要从事工程热力学研究,Email:huazhen@sdut.edu.cn;通信作者 王效岳,男,博士, 教授,Email:wangxy@sdut.edu.cn。

Investigations on heat transfer characteristics in helical coils under the effects of secondary flow vortices

  • Online:2023-05-06 Published:2023-05-06

摘要: 为改进传统螺旋盘管的换热效率,通过实验和数值模拟研究了湍流水流经均匀加 热下螺旋盘管的流动和传热特性。研究重点为垂直于盘管轴向横截面内二次流的特性及其对 工作流体水和加热盘管壁间传热的影响。结果表明,仅在实验结果中发现了盘管局部努塞尔特 数振荡,但模拟结果的努塞尔特数的模拟结果绝对值与实验结果匹配良好。其原因可能是尽管 二次流存在并沿盘管轴向不规则地演变,但与主流速度相比过小,对局部传热的影响可忽略不 计。为进一步确认盘管中二次流特性,在每 180°盘管转弯处,加接一个 360°外部反向回路环。 研究发现:额外的反向回路环加强了重新流入主盘管的二次流速度,使该横截面积内二次流涡 流的数量增加。

关键词: 螺旋盘管, 传热特性, 二次流涡流, 湍流

Abstract: In order to improve heat transfer efficiency of the traditional helical coil, the turbulent flow and heat transfer characteristics of a helical coil under uniform heating of water flowing are experimentally and numerically investigated. The main study focus is on the characteristics of local secondary flows in the axial cross-section perpendicular to the coil and their heat transfer effects between the working fluid water and the heated coil wall. It is found that the absolute value of the Nusselt number of the simulation results match well with the experimental results although local Nusselt number oscillation of the coil is discovered only in the experiments rather than in the simulation results. The reason may be that, though the secondary flows indeed exist and evolve irregularly along the coil axis, their effects on local heat transfer are almost negligible since the secondary flow velocity is relatively too small compared with the main flow velocity. To further confirm the characteristics of the secondary flows in the coil, a 360°external reverse loop is added to each 180°coil turning. It is found that the additional reverse loops increase the velocity of the secondary flows reflowing into the main coil and increase the number of the secondary flow vortices in a cross-sectional area.

中图分类号: 

  • TK124