Chemical kinetics effects of lean hydrogen-air mixtures in wedge-induced oblique detonations

Oblique Detonation Wave Engines (ODWE) rely on the formation and stability of wedge-induced oblique detonations. However, some unstable configurations are reported in numerical and experimental analyses, which are related to oscillations observed after the formation of triple deck structures. In this work, we aim to compare the effect of chemical kinetics of two kind of numerical computations with prior scenarios from the literature. The simulations are conducted using two different codes, finite elements with one-step Arrhenius reaction rate, and CREAMS, WENO high-order finite differences with CHEMKIN library for detailed chemical schemes of H2.

The impact of the reaction of a lean hydrogen-air mixture in the wedge-induced detonation structure and the stability of the process is analyzed. To achieve this, different parameters are varied (wedge-angle, incident stream Mach number and Zeldovich number) to examine their influence in the transition between oblique shock wave (OSW) and oblique detonation wave (ODW). In particular, the appearance of subsonic regions in the post-shock flow induced by the temperature increase is addressed, which might affect the shock and detonation stability through wave reflection towards the front.