Abstract

The concept of using oblique detonation waves for high efficiency propulsion systems have recently generated great interest in the development of air-breathing hypersonic aircraft due to their potential increased thermal efficiency through detonative combustion. However, for the proper design of an Oblique Detonation Wave Engine (ODWE), it is critical to predict the necessary conditions and understand the formation mechanism of oblique detonation waves. In this study, numerical simulations using a Graphics Processing Unit (GPU)-based solver are performed to investigate oblique detonations induced by a two-dimensional, semi-infinite wedge using the reactive Euler equations coupled with one-step Arrhenius or two-step induction-reaction kinetics. The novelty of this work lies in the analysis of chemical reaction sensitivity on the two types of oblique detonation formation, namely, the abrupt onset with a multi-wave point and a smooth transition with a curved shock. Scenarios with various inflow Mach number regimes M0 and wedge angles θ are considered. The conditions for these two formation types are described quantitatively by the obtained boundary curves in M0-Ea and M0-kR spaces. At a low M0, the critical conditions for the transition are independent of the wedge angle. At a high flow Mach number regime with M0 above approximately 9.0, the boundary curves for the three wedge angles deviate substantially from each other. The overdrive effect induced by the wedge becomes the dominant factor on the transition type. For large Ea the flow in the vicinity of the initiation region and subsequent ODW surface also exhibit more complex features.