The determination of physical dimensions of a hypersonic three-stage compression system considering panel vibration effects

The panel vibration of air intake system that excitated by fluid-structural interaction, engine thrust variation and noise has decisive influences on the performance of an air-breathing hypersonic vehicle. The design of such type of intake system should contain the determination of configurational parameters and physical dimensions by considering both flow and structural vibrations, and a clear design path is still absent. In this paper, an intake system with three-stage external compression ramps is designed under Mach number of 6 and flight altitude of 24 km, and the configurational parameters are determined based on the shock-on-lip criterion, Oswatitsch criterion and viscous effects modification. The mode vibration characteristics of external compression ramps with panel thicknesses of 0.002 to 0.03 m are analyzed, and appropriate natural frequencies are obtained by constraint conditions of fixed four side boundaries with an additional and more realistic constraint of strengthened internal boundary. The flow field of the intake system with forced panel vibrations of compression ramps is simulated, and the effects of vibration amplitude of 0 to 0.11 m and frequency of 10 to 250 Hz on the intake performance, i.e., total pressure recovery coefficient and mass flow coefficient are clarified. The vibration effects of hypersonic flow on the compression ramp structure and intake performance are studied by fluid-structural coupling simulations. Finally, the available physical dimensions of external compression ramps are determined and a design path of intake system is developed by considering both the structural and intake performance.