Structural and thermal analysis on oblique detonation influenced by different forebody compressions in hydrogen-air mixtures

Various oblique detonation waves (ODW) structures have been investigated with the application background of ramjet engine, but effects of forebody compression have attracted little attention before. Two forebody compression models, the ESS (equal-strength-shock) compression and the SI (shock-isentropic) compression, have been introduced to study their effects on the ODW structure and thermal performance. Numerical results demonstrate that the compression method influences the ODW structure obviously, including the initiation location and the OSW–ODW transition type. Compared with the ESS compression, the SI compression leads to the downstream movement of initiation location, and the transition prefers to be abrupt rather not smooth. On the thermal features, the total pressure recovery is used to analyse the difference as the key parameter on the potential of engine impulse. The ESS compression corresponds a low total pressure loss when considering only the combustion process, while the SI compression performs better when considering the inlet–combustion whole process. Analysis on total pressure recovery gives the average total pressure recovery with flight Ma, altitude, and wedge angle. It is pointed out the SI compression has two shortcomings, including a long initiation length and a low total pressure recovery of combustion process, which should be considered in the future application.