Investigation of flow and combustion characteristics in a hydrogen-fueled scramjet combustor

This paper investigates the combustion performance of a scramjet engine in which hydrogen fuel is injected into the flow field through transverse injectors. An unsteady numerical method is developed based on the Reynolds-averaged Navier-Stokes equations. Under a Mach number of 2.5, total temperature of 1350 K, and total pressure of 1.75 MPa condition, the flow characteristics are compared with those obtained through experiments. By analyzing the non-reacting and combustion chemical reacting flows, an evolution law of the wave system is derived, and the thermodynamic parameters of the flow field are studied for hydrogen equivalence ratios of 0.1-0.5. The results show that the non-reacting flow field exhibits periodic oscillation due to the flow structures and the low-speed separation zones, where the oscillation period is 6.9 ms. In a certain degree, the transverse injection scheme reduces the propagation of shock systems in the flow channel. When the critical value is exceeded, the shock train in the isolator is very sensitive to the back pressure from the combustion release. The local low-speed regions in the flow field will lead to the aggravation of thermal diffusion, the complication of flow structures, and the reduction in the thrust performance.