关键词: 涡扇发动机;短舱进气道;唇口;关键几何参数;进气道性能

Abstract: In response to the trend of shrinking aspect ratio of nacelle of the next generation’s civil turbofan engines, the effects of the key geometric parameters of the inlet lip on flow characteristics of the nacelle inlet were carried out in order to improve the uniform of the airflow parameters at the fan face and the flow field structure of the inlet, thus improve the aerodynamic performance of the nacelle inlet. The effects of contraction ratio, lip super-ellipse index, and lip super-ellipse long-short axis ratio on nacelle inlet performance parameters were studied by CFD numerical simulation. The results show that the three key design parameters all have a direct impact on the performance of the inlet, with the most obvious impact on the distortion index. Among them, the contraction ratio has the greatest effect. When the contraction ratio changes by 0.025, the rate of the change of distortion index can reach a maximum of 50%. The change of the contraction ratio affects the flow of throat, the change of the super-ellipse index affects the curvature of the inlet leading edge, and the change of the super-ellipse long-short axis ratio affects the curvature of the inner surface of lip. As the contraction ratio increases, the super-ellipse long-short axis ratio increases and the index of the super-ellipse decreases, the initial pressure loss and the wall friction loss increase. As a result, the total pressure recovery coefficient of the inlet decreases, and the distortion index increases.

Key words: Turbofan engine;Nacelle inlet;Lip;Key geometric parameters;Inlet performance