Studies on leading edge detection in mechanically-generated shock trains in dual-mode scramjet engines

Combustion-induced isolator shock train is modeled in this study by varying the hydrogen fuel pressure of the injector, which is located slightly upstream of the combustor in the Michigan Dual Mode Combustor (MDMC) model of ramjet/scramjet. This method of artificially generating back pressure differs from the usual, where ramps or flaps located between the combustor and the exit nozzle are used. With the correct level of back pressure, the proposed location for inducing back pressure may be more appropriate. In this study, we are particularly interested in the unsteady motion of the shock train at early time. For the four pressure values investigated, shock trains which progressively propagate toward the inlet of the isolator in time, and which were ultimately disgorged, were observed, suggesting that the selected pressure values were probably too large for use in started engines that are dynamically similar to the MDMC engine.