迎风条件下速度梯度对地面涡气动特性影响数值模拟
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摘要
以缩比的近地面短舱进气道为研究对象,通过数值计算模拟的方法得出在迎风来流条件下速度梯度对地面涡流场的结构及气动特性曲线的影响。研究表明,速度梯度是影响地面涡的主要因素。在不同的速度梯度下地面涡结构明显不同。在Y方向速度梯度下近地截面形成的地面涡是一对涡,旋转方向相反。速度梯度越大,地面涡强度,总压畸变指数明显变大。且峰值会出现滞后现象。在Z方向速度梯度下,近地截面形成的地面涡是一个单涡结构,在进气道上方也会形成一个涡体。地面涡强度、总压畸变指数会先增大后减小,峰值不会出现滞后现象。
Taking the near-ground short-slot air intake of shrinkage ratio as the research object,the influence of velocity gradient on the structure and aerodynamic characteristics of the ground eddy current field under the condition of upwind flow is obtained by numerical simulation. Studies have shown that velocity gradients are the main factor affecting ground vortices. The ground vortex structure is significantly different under different velocity gradients. The ground vortex formed by the near-surface section under the velocity gradient in the Y direction is a pair of vortices with opposite directions of rotation. The larger the velocity gradient,the greater the ground vortex intensity and the total pressure distortion index. And the peak will appear hysteresis. In the Z-direction velocity gradient,the ground vortex formed by the near-surface section is a single vortex structure,and a vortex body is formed above the inlet passage. The ground vortex intensity and total pressure distortion index will increase first and then decrease,and the peak will not appear hysteresis.
Taking the near-ground short-slot air intake of shrinkage ratio as the research object,the influence of velocity gradient on the structure and aerodynamic characteristics of the ground eddy current field under the condition of upwind flow is obtained by numerical simulation. Studies have shown that velocity gradients are the main factor affecting ground vortices. The ground vortex structure is significantly different under different velocity gradients. The ground vortex formed by the near-surface section under the velocity gradient in the Y direction is a pair of vortices with opposite directions of rotation. The larger the velocity gradient,the greater the ground vortex intensity and the total pressure distortion index. And the peak will appear hysteresis. In the Z-direction velocity gradient,the ground vortex formed by the near-surface section is a single vortex structure,and a vortex body is formed above the inlet passage. The ground vortex intensity and total pressure distortion index will increase first and then decrease,and the peak will not appear hysteresis.
引文
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5 Brix S,Neuwerth G,Jacob D. The inlet vortex system of jet engines operating near the ground:AIAA-2000-3998[R]. Reston:AIAA,2000
6 Siervi F,Viguier H C,Greitzer E M,et al. Mechanisms of inlet vortex formation[J]. Journal of Fluid Mechanics,1982,124:173-207
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8 Karlsson A,Fuchs L. Time evolution of the vortex between an air inlet and the ground:AIAA-2000-0522[R]. Reston:AIAA,2000
9 Murphy J. Intake ground vortex aerodynamics[D]. Cranfield:Cranfield University,2008
10 Rehby L. Jet engine ground vortex studies[D]. Cranfield:Cranfield University,2007
2 Klein H J. Vortex inhibitor for aircraft jet engines:2915262[P].1959-12-01
3 Trapp L G. Evaluation of engine inlet vortices usingCFD:AIAA-2012-1200[R]. Reston:AIAA,2012
4 Nakayama A and Jones J. Correlation for formation of inlet vortex[J]. American Institute of Aeronautics and Astronautics,1998,37(4):509-510
5 Brix S,Neuwerth G,Jacob D. The inlet vortex system of jet engines operating near the ground:AIAA-2000-3998[R]. Reston:AIAA,2000
6 Siervi F,Viguier H C,Greitzer E M,et al. Mechanisms of inlet vortex formation[J]. Journal of Fluid Mechanics,1982,124:173-207
7 Bissenger N,Braun G. On the inlet vortex problem:CR—132536[R]. Washington:NASA,1974
8 Karlsson A,Fuchs L. Time evolution of the vortex between an air inlet and the ground:AIAA-2000-0522[R]. Reston:AIAA,2000
9 Murphy J. Intake ground vortex aerodynamics[D]. Cranfield:Cranfield University,2008
10 Rehby L. Jet engine ground vortex studies[D]. Cranfield:Cranfield University,2007