Research on the combustion organization mechanism of synchronized injection in the upstream and downstream of the cavity in scramjet

This investigation presents experimental study on the synchronized fuel injection scheme of the upstream and downstream in cavity under the supersonic inflow condition of Mach 2.92, revealing the combustion organization mechanism of the synchronized injection in the scramjet. The results show that under the same global equivalence ratio, synchronized injection in the upstream and downstream of the cavity plays an important role in reducing ignition delay, combustion oscillation, and improving flame stability. The combustion of the downstream jet can promote the combustion inside the cavity, especially at the rear edge of the cavity, while the upstream jet can provide a large amount of high-temperature products and free radicals for the downstream jet, greatly promoting the combustion process of the downstream jet.