Experimental and mechanism investigation of mixing characteristics in alternating wedge struts with expansive trailing edges

The alternating wedge strut, serving as both an injector and a vortex generator, has great potential for application in the scramjet combustor. The expansive trailing edge structure can further enhance the mixing performance of the alternating wedge strut. To enhance the performance of scramjet engines, it is essential to investigate the fuel/air mixing characteristics and mechanism downstream of alternating wedge struts with expansive trailing edges. The research focused on the impact of two different fuel injection schemes on the air/fuel mixing process and plume morphology. The optical diagnostic technique, particle laser-induced fluorescence, was employed to measure fuel plume morphology at various downstream locations under ambient temperature conditions. The results show that the expansive trailing edge significantly enhances the vertical diffusion of the fuel, leading to distinct plume characteristics. Compared to the strut injecting fuel into the edge of the streamwise vortex, the strut injecting fuel into the core of the streamwise vortex results in a larger fuel plume area with a more uniform distribution. Additionally, a streamwise vortex model was established to investigate the vortex dynamics and mixing mechanisms behind the strut from a mechanistic perspective. The simulation results indicate that the model demonstrates good performance in forecasting the dynamics of streamwise vortices and the evolution of fuel plume morphology.