无隔道超声速进气道附面层排除特性飞行试验研究

Flight Test and Evaluation for Boundary Layer Diversion Characteristics of Diverterless Supersonic Inlet

关键词:  无隔道超声速进气道  飞行试验  风洞试验  附面层排除特性  飞行马赫数

Key words:  Diverterless supersonic inlet（DSI）  Flight test  Wind-tunnel test  Boundary layer diversion characteristics  Mach number

摘要:

为了分析评估歼击机无隔道进气道附面层的排除特性，设计搭建鼓包表面附面层压力梯度测量试验系统，进行了不同飞行高度、马赫数和姿态角等工况下的飞行试验。通过对飞行试验数据的整理、计算和对比分析同型号的缩比模型风洞试验结果，研究了无隔道进气道鼓包表面附面层排除特性。研究结果表明：稳定平飞时，在亚声速范围内，随着飞行高度的增加，鼓包构型对附面层的排除效果增大，而在超声速范围内，变化规律相反；在接近马赫数1.8及以上飞行工况下，鼓包表面附面层的扫除能力有所减弱，附面层气流分离加速，进而会造成较大的进气压力损失和畸变。单纯迎角飞行有利于增强附面层的排除能力；而带侧滑角飞行时，附面层压力系数曲线的拐点沿鼓包中心线平行向“背风面”偏移，偏移量与侧滑角成正比，进气道鼓包表面“迎风面”附面层排除能力增大，而“背风面”受气流分离影响而减弱。

Abstract:

In order to analyze and evaluate the boundary layer diversion characteristics of a fighter’s diverterless supersonic inlet， a boundary layer pressure gradient measurement test system for the bump surface was designed and built， and flight tests were carried out at different heights， Mach numbers， and attitude angles. By sorting， calculating the flight test data and comparing the flight test data with the wind-tunnel test data of the scale model， the boundary layer diversion characteristics of the diverterless supersonic inlet are studied. The research results show that： in the stable level flight， in the subsonic range， as the flying height increases， the elimination effect of the bump structure on the boundary layer increases， while in the supersonic range， the law is reversed. In the vicinity of Mach number under the flight conditions of 1.8 and above， the boundary layer diversion ability on the bump surface is weakened， and the separation on the boundary layer is accelerated， which will cause large pressure loss and distortion. Flight with angle of attack only is conducive to enhancing the ability to divert the boundary layer. When flying with a angle of sideslip， the inflection point of the pressure coefficient curve of the boundary layer is shifted parallel to the “backward surface” along the center line of the bump， and the offset is proportional to the angle of sideslip， the ability to divert the “windward” boundary layer on the bump surface increased， while the “backward surface” is weakened for the airflow separation.