摘要
在2.4 m跨声速风洞进气管路T型冲击三通连接处和隔板位置,每隔一定时间会出现裂纹,影响了风洞的安全稳定运行。为了解裂纹出现的原因,同时为改进设计提供依据,采用CFD(computational fluid dynamics)对风洞现有三通和优化方案进行了对比。控制方程为三维黏性不可压缩Navier-Stokes方程。结果表明:无隔板时,三通内的流动为最常见的类型,支管内存在3个分离区,在转向过程中形成第1分离区,即马蹄涡;随后是第2分离区,一对反向旋转的旋涡,即Dean涡,及三通顶部壁面形成第3分离区。流场沿y=0 mm和z=0 mm平面基本呈对称分布。有隔板时,流场的左右和上下结构均不对称;在隔板和外侧壁面间的角点形成范围较小的驻涡,在支管内形成不稳定的螺旋状分离涡,致使气流振荡,从而使得三通连接和隔板处管壁出现裂纹。根据上述流态设计了管路优化方案和整流装置,优化后能有效减小或消除分离;其中去掉隔板最简单易行,可以解决裂纹的问题。
Cracks may occur at the connection of the impacting T-junction and the position of the clapboard at regular intervals in intake pipelines of 2.4 m transonic wind tunnel.In order to understand the causes of cracks and provide a basis for improving design,CFD(computational fluid dynamics)was used to compare the existing tee and optimization schemes in wind tunnel.The governing equations are three-dimensional viscous incompressible Navier-Stokes equations.The results showed that the flow in the tee was the most common type without clapboard.There were three separation zones in the branch pipe.The first separation zone was horseshoe vortex,followed by the second separation zone.A pair of reverse rotating eddies,Dean eddies,and a third separation zone were formed on the top wall of the tee.The flow field was basically symmetrical along the y=0 mm and z=0 mm planes.When there was a clapboard,the left and right structures of the flow field were asymmetrical and the upper and lower structures were also asymmetrical.A small range of standing vortices were formed at the corner between the clapboard and the outer wall,and unstable spiral separation vortices were formed in the branch pipe,resulting in air flow oscillation and causing cracks in the pipe wall at the tee connection and the clapboard.According to the above flow pattern,pipeline optimization scheme and flow control device were designed.Separation zones could be effectively reduced or eliminated.Removal of the clapboard was the simplest and easiest way to solve the problem of cracks in the pipe.
作者
丛成华
秦红岗
任泽斌
陈吉明
CONG Chenghua;QIN Honggang;REN Zebin;CHEN Jiming(State Key Laboratory of Aerodynamics,China Aerodynamics Research and Development Center,Mianyang Sichuan 621000,China;Facility Design and Instrumentation Institute,China Aerodynamics Research and Development Center,Mianyang Sichuan 621000,China)
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2020年第2期235-243,共9页
Journal of Aerospace Power
基金
空气动力学国家重点实验室基金(SKLA2013A0208).
关键词
T型冲击三通
对称分离
非对称流场
流动控制
型面优化设计
impacting T-junction
symmetry separation
asymmetry flow field
flow control
shape optimal design
作者简介
丛成华(1979-),男,副研究员,硕士,主要研究方向为计算流体力学、风洞气动设计及流动控制。
