一种双S弯非常规进气道地面工作状态的试验

对一种双S弯非常规进气道进行了地面工作状态下的试验研究,得到了该类进气道的地面工作特性,结果表明:(1)双S弯非常规进气道在地面工作状态下,随着出口马赫数的增加,总压恢复系数呈下降趋势;稳态周向畸变指数、紊流度和综合畸变指数均上升;稳态径向畸变指数变化不大.(2)与飞行状态下的高速风洞流场控制试验研究结果相比,在相同的出口马赫数下,地面抽吸试验中进气道出口截面的总压恢复系数较低,稳态周向畸变指数、紊流度和综合畸变指数较大,本研究的双S弯非常规进气道在出口马赫数Mae=0.45时,总压恢复系数为0.90,稳态周向畸变指数达到了9.24%,紊流度为4.6%,综合畸变指数为13.85%,畸变比较大,超出了一般发动机的承受范围.(3)在地面抽吸状态下,进气道出口马赫数Mae≤0.37时,综合畸变指数W≤10%,说明发动机可在适当的降转速下稳定工作,随着飞机在地面滑行速度的增加,满足发动机稳定工作要求的进气道最大出口马赫数不断增加.

Experimental study of a serpentine inlet under ground running

Experiments of a serpentine inlet under ground running have been done and described in this paper.The study was performed in a low speed wind tunnel with an independent air-pumping system.It contains air-pumping tests at zero and different speeds of the free stream.The results show that:(1)When the inlet Mach number of the flow at exit increases,the total pressure recovery decreases,and the circular steady total pressure distortion coefficient,turbulence intensity and synthesis distortion increase.In comparison with the results measured in highspeed wind tunnel tests for the serpentine inlet at the same exit Mach number,the total pressure recovery is lower and the circular steady total pressure distortion coefficient,turbulence intensity and synthesis distortion are larger.(2)Under ground air-pump running,when the serpentine inlet is running at the exit Mach number Ma_e=0.45,the total pressure recovery coefficient equals 0.90,circular steady total pressure distortion coefficient equals 9.24%,turbulence intensity equals 4.6%,and synthesis distortion equals 13.85%,so it can be seen that the distortion of the flow delivered by the inlet may be too large to fit the engine.(3)When the air-pumping system and the wind tunnel are operating together,as it happens when the plane is ground taxiing,the performance of the inlet is getting better with the wind speed increasing.