中心体位置对轴对称可调进气道跨声速流动特性的影响研究

Effects of Centerbody Position on Flow Characteristics of an Axisymmetric Variable-Centerbody Inlet at Transonic State

关键词:  轴对称可调中心体进气道  中心体位置  跨声速  口部波系  节流特性

Key words:  Variable-centerbody axisymmetric inlet  Position of centerbody  Transonic state  Shock wave system at entrance  Throttling characteristics

摘要:

为了探究跨声速状态下轴对称中心体可调进气道的流动特性，设计了一个轴对称变几何进气道，研究了其在Ma₀=1.1时不同中心体调节位置下的流场特征和气动性能，获得了其口部和泄流腔内流动特性、节流特性以及气动性能。结果表明：四个不同中心体位置的进气道在Ma₀=1.1状态下呈现出3种不同的口部波系结构，分别为：全亚声速流动、“λ”波系和单道脱体弓形波。当中心体位置靠后时，进气道为混压式，入口处为全亚声速流动，肩部泄流腔始终处于正常泄流状态；当中心体位置靠前时，进气道为外压式，入口会呈现“λ”波系与单道脱体弓形波两种情况，泄流腔在低反压下为倒吸状态，而在高反压下转变为泄流状态。进气道处于外压式时在中心体一侧会产生大尺度的分离，抗反压能力相比处于混压式时略差。随着中心体前移距离的增大，进气道的流量系数和总压恢复系数都呈现不同程度的下降，其中总压恢复系数下降了14.8%，流量系数下降了7.5%。因此，对于本文研究的进气道而言，跨声速状态下其工作在混压式状态时具有较好的工作性能，其对应的较佳内收缩比为1.05。

Abstract:

To investigate the flow characteristics of an axisymmetric inlet with variable positions of centerbody at transonic state， an axisymmetric variable-geometry inlet is designed. Flow characteristics at the entrance and bleeding chamber， throttling characteristics and aerodynamic performance of the inlet with different centerbody positions are obtained by numerical simulation under the free flow Mach number of 1.1. The results show that 3 types of shock wave systems appear at the entrance， which includes full subsonic flow， λ-type shock waves and single detached bow shock. When the centerbody locates backward， the inlet is a mixed-compression type one with full subsonic flow in the entrance， and the shoulder bleeding chamber is always normally operated. When the centerbody locates forward， the inlet is an external-compression type one with λ-type shock waves or single detached bow shock， and the chamber is at the state of suction under low back pressure， transforming into an inversion state under high back pressure. In addition， a large-scale separation babble lies on the side of centerbody when the inlet works in the external-compression state， which have worse capability of resisting the adverse pressure gradient than that in the mixed-compression state. With increasing the centerbody translation distance， the mass flow coefficient and total pressure recovery coefficient of the inlet decrease to some extent， among which the total pressure recovery coefficient decreases by 14.8% and the mass flow coefficient decreases by 7.5%. Therefore， when the studied inlet work in the mixed-compression state， it has better performance at transonic state， and the corresponding internal contraction ratio is 1.05.