旋转条件下U形通道转弯段形状对流动和传热特性的影响  

Effects of Turn Shapes on Flow and Heat Transfer Characteri-stics in U-shaped Channel Under Rotating Conditions

作　　者：由儒全 刘泽萱 李海旺 施锦程 陶智 Ru-quan You;Ze-xuan Liu;Hai-wang Li;Jin-cheng Shi;Zhi Tao(Research Institute of Aero-Engine,Beihang University;National Key Laboratory of Science and Technology on Aero-Engines Aero-Thermodynamics,Beihang University)

机构地区：[1]Research Institute of Aero-Engine,Beihang University [2]National Key Laboratory of Science and Technology on Aero-Engines Aero-Thermodynamics,Beihang University

出　　处：《风机技术》2023年第3期33-42,共10页Chinese Journal of Turbomachinery

基　　金：National Natural Science Foundation of China(51906008)。

摘　　要：In this paper,the flow and heat transfer characteristics in U-shaped channel with three different turn shapes are studied.The rotation number ranges from 0~0.251,Reynolds number are 11500,23000,34500,respectively.The results show that the flow separation and reattachment in the turning section are the key factors affecting the local heat transfer and pressure loss of U-shaped channel.The square turn will generate corner vortices at the outside of the turning section,and the size of the inner separation vortex and reattachment vortex is larger than that of the other two turn shapes.The existence of vortex system will increase the mixing and enhance heat transfer,but increase the pressure loss,so its relative Nusselt number and pressure loss are the largest.There are corner vortices on the outside of the turning section of the channel with a inner circle turn and outer square turn,but the arc-shaped inner edge makes its separation delay and the separation vortex decrease,and the size of the reattachment vortex also decreases.The arc shaped outer edge of the channel with circle turn in both inner and outer further inhibits the generation of corner vortices,so its relative Nusselt number and pressure loss are the lowest.Rotation will cause the fluid to deflect under the influence of Coriolis force,strengthen the heat transfer on the trailing surface of radial outflow and the leading surface of radial internal flow,and generate secondary flow and separation vortex in the turning section,resulting in the change of vortex structure in the turning section.With the increase of rotation number,the Nusselt number of the three types of turning section structures increases.The thermal performance factor of the three channels increases with the increase of rotating speed,and the channel with a inner circle turn and outer square turn is the highest,which is 9.6%higher than the channel with circle turn in both inner and outer on average,and 17.8%higher than the channel with square turn in both inner and outer.

关 键 词：ROTATION U-shaped Channel Pressure Loss Nusselt Number 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]