Mixing control by wall flush-mount injectors in dual-mode combustor

Interaction between the fuel-jet / cross-flow mixing and a pseudo-shock system was experimentally investigated to evaluate the possibility of mixing control by wall flushmount injector configuration during a dual-mode operation. The fuel-jet was simulated by inert helium injection, and the pseudo-shock wave system was generated by backpressurizing a Mach 2.5 airflow with a mechanical valve. Three difference injection schemes, perpendicular injection through a circular orifice, perpendicular injection through a stinger-shaped orifice, and angled injection through a circular orifice, were employed, and changes in mixing characteristics due to interaction with the pseudoshock system were investigated. Interaction with the pseudo-shock system resulted in suppression of plume core penetration, enhancement of injectant diffusion especially in spanwise direction, and elimination of stinger-shaped orifice's superiority over the circular orifice in perpendicular case. The swept-back injection resulted in a slow mixing in near field and fast mixing in far field, so that combination with the perpendicular injection might make mixing control feasible.