爆震波逆向传播抑制特性数值仿真

Study on the Suppression Characteristics of Backward Propagation of Detonation Wave

为了发展爆震工作条件下进气涵道运动激波前传抑制技术,采用非定常数值方法开展了爆震发动机进气涵道流动特性与高频强扰动抑制技术研究。结果表明:受出口高频强压力扰动影响,涵道内存在逆向传播的运动激波。在运动激波逆向传播过程中激波强度与压力脉动强度先衰减后增强,运动激波传播速度逐渐减小直至为零。刚性障碍物高度影响运动激波传播特性。随着障碍物高度增加,压力脉动谷值逐渐降低并向下游移动,同时结尾激波向上游移动,波前马赫数降低,结尾激波强度减弱,使出口马赫数和总压恢复系数均增大;合理选取刚性障碍物高度可以有效降低压力脉动强度,当障碍物高度为进气涵道出口高度的0.07倍时,涵道内的总压恢复系数达到了0.884,脉动强度谷值最大下降36.6%,对上游的影响相对较小。

In order to develop the backward propagation suppression technology of the moving shock in the inlet duct under detona⁃tion working conditions,the unsteady numerical method was used to study the flow characteristics and high-frequency strong disturbances suppression technology in the inlet duct of the detonation engine.The results show that affected by the high-frequency strong pressure dis⁃turbances at the outlet,there are backward propagating moving shocks in the duct.In the process of the backward propagation,the strength of the shock and pressure fluctuation attenuates first and then increases.The propagation speed of the moving shock gradually de⁃creases to zero.The height of the rigid obstacles affects the propagation characteristics of the moving shock.As the height of the obstacles increases,the valley value of pressure fluctuation gradually decreases,the position of the valley value move downstream,while the termi⁃nal shock wave moves upstream,the wavefront Mach number decreases,the terminal shock strength decreases,leading to the increase of the outlet Mach number and the total pressure recovery coefficient.Reasonable size of rigid obstacles can effectively reduce the intensity of pressure fluctuation.When the height of the obstacles is 0.07 times the outlet height of the inlet duct,the total pressure recovery coefficient in the duct reaches 0.884,and the valley value of the pressure fluctuation intensity decreases by 36.6%at most,which has relatively little impact on the upstream.