Abstract: To study the effects of the entrance and exit aspect ratios on flow characteristic of the inward turning inlet， the performance of inlets with different compound modes of entrance and exit aspect ratios is simulated by setting entrance and exit shape with different aspect ratios. Multiple models are numerically simulated at the design point of Ma6. The results indicate that the ratio of the exit and entrance aspect ratios is an important parameter of the inlet performance. The total pressure recovery coefficient is high when the ratio is between 1 and 1.5. The maximum increase reaches 25.3%. The distortion index is highest when the ratio is 1. Setting different exit and entrance aspect ratios can decrease the distortion index. The maximum decline reaches 40.5%. In addition， when the entrance and exit aspect ratios are between 0.8 and 2.4， increasing the aspect ratios can reduce 25% of the inlet length at most.

Key words: Inward turning inlets；Aspect ratio；Numerical simulation；Shape transition

摘要： 为研究内转式进气道进出口宽高比对流动特性的影响规律，通过设置宽高比不等的矩形进出口形状，对不同进出口宽高比组合方式下的进气道性能进行了数值模拟。在Ma6设计点对多个模型的计算结果表明:出口与进口宽高比的比值是影响进气道性能的关键参数，该比值在1～1.5内进气道总压恢复系数较高，最大增幅达25.3%；该比值为1时进气道出口气流畸变最大，通过设置合理的进出口比值可有效减小出口气流畸变，且最大降幅达40.5%；此外，进出口宽高比在0.8～2.4内，增大进出口宽高比可最多缩短25%的进气道长度。

关键词: 内转式进气道；宽高比；数值模拟；截面渐变