Study on the Effect of Oval Tubes on Airflow Turbulence Characteristics in Wind Tunnel

椭圆翅片管对风洞气流湍流特性影响研究

¹ State Key Laboratory of Aerodynamics, China Aerodynamics Research and Development Center, Mianyang 621000, China
² Facility Design and Instrumentation Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China

Received: 14 May 2019

Abstract

The flow Turbulence characteristics of finned oval tube heat exchanger used in wind tunnel were studied by using numerical simulation method. Firstly, the reliability of the numerical method was verified by the experimental results. And then the research was focused on the comparative analysis of the characteristics of turbulent flow downstream of heat exchanger under different inflow conditions, and the influence of the tubes number and fins spacing on the airflow turbulence and the flow field distribution downstream of heat exchanger were obtained too. The results indicate that oval tubes have a significant effect for improving the flow quality when incoming flow is inhomogeneous, and the velocity distribution behind heat exchanger tends to become uniform. Inflow conditions have a slight effect on the turbulence intensity behind heat exchanger, which mainly depends on the structural parameters of heat transfer tubes. The turbulence intensity decays very quickly in the flow direction. The value is reduced to 7.5% at the cross section 600 mm downstream of the heat exchanger inlet, which agrees well with the experimental result.

摘要

针对风洞中应用的某型椭圆翅片管热交换器，开展了换热管束对气流扰动特性仿真研究。首先利用试验结果验证了数值方法的可靠性，然后通过数值仿真着重对比分析了不同来流条件下热交换器下游湍流发展变化特性，并对管排数目和翅片间距对热交换器下游气流扰动和流场分布的影响展开了研究。结果表明：热交换器换热管束对上游不均匀来流有较强的整流作用，可使流动分布趋向均匀；热交换器后气流的湍流强度受来流条件影响不大，主要取决于换热管束本身的结构参数；热交换器后气流湍流强度在入口流体流动方向上很快衰减，该型热交换器在入口下游600 mm处湍流强度即可减小到7.5%，与试验测试值吻合较好。