Theoretical Modeling on Three Operation Modes of a Scramjet Isolator

A typical scramjet engine is an airbreathing engine that performs both ramjet and scramjet engine operation for supersonic and hypersonic flights. The isolator acts as a buffer between the intake and combustor. The internal flow structures of the isolator can be divided into three modes: dual-mode ramjet, dual-mode scramjet, and scramjet mode. In this study, all three modes to precisely depict the internal flow structures of the isolator are proposed, which are based on detailed mathematical and theoretical modeling. Various comparisons and validation of the results are conducted against previous studies. The ratio of the shock train to the mixing region formed by the back pressure is analyzed. In addition, the effects of back pressure of an isolator to typical flight conditions are investigated. The pseudo-shock train structure has high-frequency oscillation to the increase of flight Mach number.