Study of dual throat nozzle internal flow characteristic

The internal flow characteristics of dual throat nozzle (DTN) under vectoring and unvectoring thrust was studied by numerical simulation. The effects of several parameters on the internal flow were analyzed. The results show that DTN can achieve larger thrust vectoring efficiency with nozzle pressure ratio (ZNPR) only at 3-4 on unvectoring thrust state (thrust coefficient arrives 0.97, mass flux coefficient 0.94). But thrust coefficient decreases rapidly with ZNPR increase. On vectoring thrust state, DTN can achieve superior vectoring thrust efficiency (arrive 4 at ZNPR=4, secondary injection=3%), and large enough thrust coefficient (0.94). DTN has a superior overall performance than throat skewing nozzle and shock vectoring nozzle. The secondary mass flux, ZNPR, cavity convergence/divergent angle, and injection angle have different effect on internal performance of DTN. In order to achieve a tradeoff between vectoring and unvectoring state, the proposed parameters of DTN are; ZNPR=3-4, secondary injection flux is about 3%, cavity divergence angle is about 10, cavity convergence angle is 20-30, injection angle of secondary is about 30 by counterflow injection.