Effects of sawtooth grooves on supersonic combustion

Abstract

A novel strut with sawtooth grooves arranged at the trailing edge of a normal strut was developed to improve the performance of a scramjet combustor. Through numerical simulations, the cold and hot flow fields of scramjet combustors with normal and novel struts were presented at an inlet Mach number of 2.0. The comparison of numerical results with experimental results has proven the accuracy of the numerical method for cold flow and hot combustion fields. The effects of sawtooth grooves on the performance and mechanism of a scramjet combustor were investigated. The results show that streamwise vortices induced by sawtooth grooves promote the macro-transport process, which promotes the diffusion of fuel to both sides of the strut and the mixing of fuel and air. Compared to the normal strut, the novel strut can reduce the distance by 24% for fuel being completely mixed and cut the length by 45.9 and 42.7% for combustion efficiency reaching 95 and 100%, respectively. The cost of this improvement is the increase in the total pressure loss by only 1%. The combustion and heat release processes were significantly enhanced by the sawtooth grooves. Therefore, the arrangement of sawtooth grooves at the trailing edge of the strut can effectively improve the performance of the scramjet combustor, which is promising for further research and optimization.