【作者】 康磊；

【导师】 黄洪雁；

【作者基本信息】 哈尔滨工业大学 ， 动力机械及工程， 2009， 硕士

【摘要】 进气道的作用主要是对飞行器飞行过程中迎面高速来流进行减速增压并整流,为发动机提供充足的均匀高压流体。随着现代飞行器的速度和机动性的不断提高,对发动机的要求越来越高,而进气道对发动机工作性能影响显著,因此进气道性能的好坏成为影响飞行器飞行性能的关键因素之一。本文研究的进气道,具有位于几何中心线下方的“C”型入口,经过“S”弯后进气道的圆形出口中心位于几何中心位置。设计过程中,先对进气道进行参数化处理,将进气道的几何形状表述为有限的控制参数,通过控制参数的调整,精心选择进气道的几何中心线、截面面积沿流动方向的变化规律、由“C”型向“O”型的截面渐变规律等,最终设计出了满足几何和气动参数要求的进气道形状。设计计算中,采用CFX进行流场模拟,采用Isight调节进气道成型的控制参数实现自动寻优,对不同方案的流场进行了详细分析。“S”弯的设计是影响进气道出口流动的关键因素。计算表明,“S”弯折转比较剧烈使得流场附面层增厚,同时也带来了较大的能量损失;但是当折转过于平缓时,扩张型面比较大的方案(出口半径较大)使得势流核心区位置偏离中心位置,扩张壁面附近的流体速度得不到补充,会产生严重的流动分离;因此“S”弯的折转程度适当时,才能改善流场的均匀性;削弱附面层,畸变度减小;得到比较均衡的出口流场。对比参考进气道和优化后的进气道,可以看出优化后的进气道比原来的进气道气动性能得到了改善:在相同的边界条件下,总压恢复系数系数明显提高;对于小出口尺寸的两个方案,优化之后的进气道附面层明显变薄,总压不均匀度降低,对大出口尺寸方案由于设计难度较大,优化效果不明显;更多还原

【Abstract】 The main function of the inlet is to transfer the kinetic energy of incoming airstream into pressure head and supply the uniform high pressure source airstream. With the development of aircraft speed and maneuverability, the requirement performance of the aircraft engine became more and more prominent. The inlet has the significant influence on aircraft engine performance. Therefore, it became the significant bottle neck of aircraft engine performance improvement. This paper study certain running condition which parameters are in the middle and successfully design a series of S-shaped inlets with C-shaped section ,whose Aoutlet/ Ainlet ( Aoutlet -outlet area, Ainlet -inlet area) are different. The design approach includes choosing the inlet centerline shape and cross-section variation law of the area. The different outlet radiuses of internal passage has been numerical investigated, Calculating inlet modle using software CFX and then export the result in the different radius of the channel scheme, and then use Isight optimization software In order to obtain the optimal structure, Explain and analyze characteristics of Internal flow in detail.Compared the optimized inlet with original inlet, we can see the outcome is in better condition ;lt have a lot of improvement in the same boundary conditions, the coefficient of total pressure recovery(σ) can be improved a lot, Boundary layer of two groups of optimization outcome become thiner. Also the level of total pressure non-uniform is decreased in two groups , while another group have no change on the whole; hence it show us the flow of outlet bend been More and more stable; S-shaped inlet make access more and more stable in outlet field, but also it cause a larger energy loss; as the radiusof outlet become larger; boundary layer become thicker of inlet flow , the velocity near the wall become weak; distortion can reduce these losses, as while reduce the perpendicularity and increase the vertical gradient in outlet field , the boundary layer weakens, A substantial increase in distortion.更多还原