Scramjet Isolator Shock-Train Leading-Edge Position Modeling Based on Equilibrium Manifold

Abstract

A dynamic model showing the relationship between backpressure and shock-train leading edge (STLE) is necessary in the development of a STLE automatic control algorithm. In this research, a nonlinear dynamic model based on equilibrium manifold expansion is presented to locate the STLE position in a large range of operation conditions. The initially started flow field of a hypersonic inlet at different throttling ratios was experimentally studied at freestream Mach numbers 4.5–6.0. The nominal STLE position was defined by the pressure ratio method. The variation of STLE position with backpressure and freestream Mach number was then discussed. Testing with the experimental data, past models could only be used locally, whereas for large range of operation conditions they lose effectiveness. Therefore, the nonlinear dynamic modeling method based on equilibrium manifold is introduced to solve this problem, the simulation results, and comparisons at large range of operation conditions show its validity.