Numerical study on initiation of oblique detonation wave by hot jet

Reliable detonation initiation is critical in detonation engines, especially for oblique detonation engines covering a wide range of flight regimes. The widely-studied oblique shock initiation usually leads to a significant variation in initiation length, making it difficult to adapt to the wide range of flight conditions. In this study, hot jets in the induction zone, i.e. behind the oblique shock, are introduced to explore the possibility of jet initiation, providing a potential method for initiation control. Results show that hot jet can decrease the initiation length to achieve rapid initiation and change the wave structure simultaneously, which is attributed to the oblique shock induced by a gaseous wedge. Thermal analyses of jet-initiated ODWs are also conducted through total pressure recovery. Results indicate that jet-initiated ODWs have a slightly better total pressure recovery than the original ODW. Furthermore, the jet angle and position are varied to analyze their effects on the initiation position, which is insensitive to the former while sensitive to the latter. A large jet angle may lead to a strong solution of secondary oblique detonation, which has not been previously reported.