Experimental and numerical study of Richtmyer-Meshkov instability (RMI) induced mixing enhancement has been conducted in a liquid-fueled scramjet engine with a central strut. To generate the RMI in the scramjet engine, transverse high temperature jets are employed downstream the strut injector. Compared to the transverse ordinary temperature jet, the jet penetration into the supersonic airstream of high temperature jet increases by 60%. The numerical results indicate that the RMI phenomenon markedly enhances the mixing efficiency (up to 43%), which is necessary to initiate the chemical reactions. Ground experiments were carried out in the combustor, which verify the numerical method from the perspective of wall pressures of the combustor. In particular, the experiment results indicate that the RMI can benefit flame-holding due to the mixing enhancement. 1. Introduction The supersonic combustion ramjet (scramjet) engine is expected to the most efficient propulsion system in the hypersonic flight regime [1]. And it requires rapid mixing between fuel and air, due to the limited time and space available for chemical reaction in the combustor [2]. The Richtmyer-Meshkov instability (RMI) occurs when an interface between two fluid layers of different thermodynamic properties undergoes impulsive acceleration, typically caused by an incident shock wave, which can affect the rate of mixing [3, 4]. Therefore, we explore the application of RMI phenomenon for kerosene-air mixing enhancement in a strut-based scramjet combustor. Strut injectors offer the possibility to inject the fuel in the supersonic core region [5, 6]. For the application of the struts, technical difficulties are an increase in the distance (combustor length) to achieve adequate mixing [7] and flame stabilization, especially for a thin strut. Previous experiments [8] and numerical simulations [9] demonstrate flame-holding of the strut-based scramjet configure depends on the subsonic recirculation created in its base, and therefore an increase of the thickness of the strut (i.e., of the blockage ratio in the combustor channel) enhances the capability of the strut injector for ignition and stabilization of the flame. However, a thick strut can lead to significant drag and total pressure losses increase. Much work has so far been done on RMI phenomenon. Some researchers [10, 11] analyzed the effect of initial conditions on the rate of mixing due to RMI phenomenon. Thornber et al. [12] numerically studied flow physics of a reshock Richtmyer-Meshkov induced turbulent mixing layer using high-order
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