Research On Variable Geometry Inlet With Concave Shockwave Compression Surface Operating In A Large Mach Number Range

Due to the shortness, low friction, high performance in off-design Mach, good ability to adapt fornon-uniform intake flow, curved shock wave compress system is the ideal hypersonic impulse systemin the future.To adjust for wide Mach condition, the feasibility and method of using flexible material toachieve the geometry-variable hypersonic curved shock wave compress system is studied in this paper.Its aerodynamic mechanism is discussed first. After comparing its performance with thefixed-geometry inlet, the aerodynamic benefit of geometry-variable inlet is gained. Considering thegeometry structure, three methods of using high-pressure flow from isolator to drive the geometryvariation is proposed, and their characteristics are discussed.Both theory and numerical simulation are used to study the method of calculate thefluid-structure interaction problems. External compression wall is simplified as a cantilever beam.Deflection equation for arbitrary load is obtained. Analysis method for fluid-structure is theoreticallydiscussed. To solve the variation of complicated geometry in hypersonic flow, the method ofcombining the CFD and FEM software to calculate the fluid-structure problem is studied. Thesemethods are used to design and adjust the inlet geometry to ensure shock on lip under wide Machnumber condition.An experiment of variable geometry curved shock wave compress hypersonic inlet using flexibleplate is designed. The variation pattern of fluid parameter (include pressure distribution, outflowprofile, etc.) when the flexible compress wall is driven by a screw is obtained. In addition to this,some preliminary study is made on the feasibility of using smart material to drive the compresssystem geometry variation. The response characteristics of using shape memory alloy for compresssystem is observed.