Large eddy simulation on the interaction effect of shock waves induced by wall ramps on strut flame

Struts are a commonly used structure in scramjet engines. Their advantage lies in their ability to serve as both fuel injectors and flame stabilizers under high-speed conditions. In a strut-based combustor, there exist complex shock-wave structures and shock-wave-flame interactions. In this work, wall ramps were placed on the walls of the strut-based combustor to study the impact of oblique shock waves on the strut-jet flame. Three ramp-installation schemes were designed, and three-dimensional transient numerical studies were carried out using large-eddy simulation based on the OpenFOAM platform. The large-scale vortex structures were captured, and the interaction between the oblique shock waves induced by the ramps and the strut-jet flame was analyzed from the perspective of shock wave and vortex interactions. The dimensions of the struts and ramps were customized. The numerical results indicate that the shock waves induced by the ramps can significantly affect the strut-jet flame. Under strong compression, large-scale vortex structures are formed, and the flame mixing layer expands, promoting the mixing of the fuel jet and air, thus enhancing combustion. The stabilization mechanism of the strut-jet flame under the influence of the ramp-induced shock waves was analyzed. Additionally, a mechanism analysis of the flow-blockage phenomenon occurring in the simulation study was conducted. This research contributes to a better understanding of the flow-combustion phenomena occurring within the strut-based combustor, providing a certain theoretical basis and guiding solutions for the design and research of strut-based combustors in scramjet engines.