Investigation on the effect of the leading angle of the strut on the stabilization characteristics of lifted jet flames

Abstract

To achieve stable combustion within supersonic combustors, the strut-based mixing augmentation techniques are commonly employed. Large Eddy Simulations (LES) are employed to capture the intricate details of the combustion process in this study, focusing on the influence of shock waves induced by the leading edge of the strut and recirculation zones formed at the trailing edge on flame structure and stability. The effects of five struts with different leading edge angles on the stabilization characteristics of lifted jet flames were investigated, and a novel wedge-shaped strut was proposed. The results reveal that variations on the leading-edge angle of the struts lead to significant differences in the morphology of the jet flames. Under conditions permitting stable combustion, a strut with a 5° leading edge half-angle exhibits the highest combustion efficiency, though the combined effects of shock waves and recirculation zones in the 7° leading edge half-angle strut are also noteworthy. Based on these findings, a novel wedge-shaped strut design is introduced, which combines the characteristics of both strut types. The novel wedge-shaped strut achieves a combustion efficiency of 97 % at the slight cost of additional total pressure loss, providing a foundation for further optimization.