The Effect of Hot Gas Injection on Thrust Vector Control in a Double-Divergent Nozzle—A Numerical Investigation

Double-divergent nozzle (DDN) is an altitude adaptable rectangular nozzle which has no mechanical elements to gain altitude compensating property, which results in a lighter nozzle. In this work, the thrust vectoring using a secondary hot gas injection in a DDN is investigated. The effects of injection pressure, injection location, injection angle, inflection angle, and nature of injectant on thrust vectoring performance are investigated using numerical simulation. Initially the effect of different propellant is studied under hot flow conditions. It is observed that, H2O2 shows better performance compared to other mixtures, and it is used for remaining studies. Further, the thrust angle is affected by both the injection pressure and the injection site. The lateral thrust is increased with higher injection pressure and the injection closer to the exit of the nozzle. When the injector slot angle is high, the primary downstream vortex vanishes and a strong secondary upstream vortex is created. This shift in the primary upstream vortex away from the core flow advances the shock separation. More deflection of propellants is obtained at higher injection angle. Finally, it is noted that, as the inflection angle increases the deflection of combustion gas also increased to ensure better thrust vectoring.