Study on the Effect of Oxidative Jet and Vortex Structure in Fluidic Throat Combined with Thrust Vector Control

Abstract

To examine the impact of oxidative jets on the thrust vector angle, secondary combustion efficiency, and combustion chamber pressure, inert gas (nitrogen) and pure oxygen are injected into the primary flow, which includes combustible components, at various locations in the divergence section and throat using different injection techniques. The simulations utilize Reynolds-averaged Navier-Stokes equations coupled with the SST $k$ - $\omega$ turbulence model in two-dimensional numerical simulations and large-eddy simulation in three-dimensional studies. The numerical method is validated through schlieren experiments, and the vortex is identified using the Liutex-Omega method. The vortex structures and flow characteristics are analyzed. The results indicate that, at the same flow rate, the vector control effect of pure oxygen is superior to nitrogen only in the divergence section, but inferior to nitrogen in both the divergence section and throat. However, with improved vector control, the peak of the vector angle is achieved at a lower flow rate in the case of pure oxygen. When the secondary flow is introduced only in the divergence section, the flow ratio corresponding to the peak point in the pure oxygen case is approximately 14.3% earlier than that in the nitrogen case. The introduction of the pure oxygen jet enhances the secondary combustion efficiency of the primary flow, but to a limited extent. Additionally, when the jet is introduced at the throat, the effect of the pure oxygen case on adjusting the combustion chamber pressure is inferior to that of the nitrogen case. Concerning flow details, the trailing lower vortex replaces the trailing major vortex to become the highest magnitude vortex when the momentum flux ratio is small.