Stabilization of wedge-induced oblique detonation waves in pre-evaporated kerosene–air mixtures with fluctuating equivalence ratios

The present investigation numerically studies the wedge-induced oblique detonation waves (ODWs) in unsteady inflows with fluctuating fuel–air equivalence ratios. The Navier–Stokes equations with a two-step chemical reaction scheme are solved for modeling the reacting flow. The inflow is introduced with a continuous sinusoidal disturbance of the equivalence ratio to analyze the influence of disturbance on the initiation and stabilization of ODW. For a smooth transition from shock-induced deflagration to detonation in a steady flow, the effects of fluctuating amplitude and disturbance cycle numbers are studied. Increasing fluctuating amplitude affects the ODW initiation for a low-to-medium amplitude and results in the unstable ODW surface with more triple points for a high variation. The fuel-lean mixture weakens the ability to form the triple points. The unsteady transverse detonation wave is generated during the stabilization of ODW in high-amplitude fluctuating flow, and its dynamics depend on the spatial distribution of reactive mixtures. The stabilization of ODW is found to be insensitive to the disturbance cycle number, and the increase in fluctuating frequency mainly disturbs the ODW surface. The fuel-rich mixture leads to the oscillation of transition wave structures around the initiation region. Generally, the disturbed ODW front can re-adjust with local unstable features after a dynamic process and stabilize on the wedge. The wave structure of ODW becomes more robust in the fuel-lean inflow disturbance.