Influence of Aft Deck on the Flow Characteristics of a Serpentine Shock Vector Control Nozzle

A convergent-divergent serpentine shock vector controlling nozzle can significantly reduce the infrared and electromagnetic radiation intensity of the engine tail，and realize the thrust vector control in the pitch direction of supersonic aircraft，which greatly enhances the stealth and maneuverability of the aircraft. As the nozzle with a rectangular outlet needs to be integrated with the rear fuselage，one side wall is usually extended as an aft deck，so that the deflection rule of the tail jet is different from that under the symmetrical nozzle outlet. In this paper，numerical simulation is used to compare the flow characteristics of serpentine shock vector controlling nozzle with and without an aft deck，and then the influences of the aft deck length and angle on the performance of serpentine shock vector controlling nozzle with an aft deck are studied respectively. The results show that under certain working conditions，the oblique shock wave induced by secondary flow injection from the upper wall will be reflected from the aft deck，which is not conducive to the generation of downward thrust vector angle. When there is no open separation of the aft deck surface，the outflow from the lower wall will flow along the aft deck surface，so the increase of the length or angle of the aft deck will deflect the jet velocity axis downward.