Pressure-Gain Combustion Using Shock–Flame Interaction

Abstract

One method of significantly improving the performance of gas turbine engines is to use the thermodynamically more efficient unsteady combustion with pressure rise. In this work, the feasibility of using the interaction of shock waves with a flame to achieve pressure-gain combustion is investigated. A new analytical model is described. The pressure rise and entropy suppression of a single shock–flame interaction event is predicted for the first time. The model is quasi-one dimensional, with the shock wave planar and the flame laminar premixed. Given known initial flowfield and flame geometry, as well as the incident shock Mach number, the model allows the calculation of a fully defined one-dimensional flowfield that is formed at the end of a single shock–flame interaction event. The analytical model is successfully verified using experimental data on methane-oxygen-argon flames. It is found that a single shock–flame interaction event temporally generates a dramatic increase in pressure compared to isobaric combustion with the same unburned gas conditions. The associated increase in temperature remains at a relatively moderate level. Further, combustion entropy rise is significantly reduced through a single shock–flame interaction event.