唇口几何参数对短舱进气道性能影响数值研究

针对下一代民用涡扇发动机短舱长径比不断缩小的发展趋势,为改善发动机进口气流参数分布不均、改善进气道的流场结构、提高其气动性能,开展了进气道唇口关键几何参数对短舱进气道流动特性影响的研究。通过CFD数值模拟方法研究了进气道收缩比、唇口超椭圆指数以及唇口超椭圆长短轴比对短舱进气道性能的影响。研究发现,这三个设计参数改变时,均会对进气道性能产生直接的影响,对畸变指数的影响最明显,其中收缩比改变的影响最大,当收缩比每改变0.025,畸变指数的变化率最大可达到50%。进口收缩比的改变影响喉道截面的流动,超椭圆指数变化影响了进口前缘曲率的变化,而超椭圆长短轴比变化影响了进气道唇口内型面的曲率;超椭圆长短轴比越大,超椭圆指数越小,收缩比越大,唇口初始压力损失越大,壁面摩擦损失越大,进气道总压恢复系数越低,畸变程度越高。

Numerical Study on Effects of Lip Geometric Parameters on Performance of Nacelle Inlet

Low-speed simulation aerodynamic design with four repeating stages was conducted for verifying performance of a multistage axial compressor exit stage, and two-dimensional design was given first place with three-dimensional numerical verification as a supplement. Similar 2D flowfield and profile surface normalized velocity distributions were established between low and high-speed compressor used the same design system. Then, the comparison between the 3D numerical results of the low and high-speed compressors showed that the pressure rise coefficient characteristics were consistent, the flowfield was similar, and the dimensionless velocity of the blade surface kept the same trend from the design point to the stall point, which further validated the feasibility of 2D design. Using the same design system is conducive to forming a benign cycle of high-low-high speed, improving the design system based on througnflow program and accumulating design experience.