INVESTIGATION ON THE FLOW MECHANISM AND DYNAMIC RESPONSE PERFORMANCE OF EFFICIENT FLUIDIC THRUST VECTORING SERPENTINE NOZZLE

High maneuverability, wide speed range, and strong stealth are the key technical requirements for the exhaust system of advanced fighters. The main technical manifestation of high maneuverability and wide speed range is thrust vectoring technology, and the main technical manifestation of strong stealth is the serpentine nozzle. The efficient fluidic thrust vectoring (FTV) serpentine nozzle not only has the above advantages, but also has simpler structure, lighter weight, and quicker vector response. There are complex pressure gradients and strong swirl characteristics inside the serpentine nozzle, such that efficient FTV design of the serpentine nozzle faces greater challenges than conventional nozzles. Therefore, it is important to conduct in-depth study on the efficient FTV serpentine nozzle. This paper conducted a numerical investigation on the flow mechanism and dynamic response performance of an efficient FTV serpentine nozzle. Results show that the depth of the secondary injection can be effectively increased by setting an additional auxiliary injection in front of the secondary injection, which results in the increase of the angle of the induced shock wave and a more obvious deflection of the mainstream. For the high pressure ratio, the time of thrust vectoring formation of the efficient FTV serpentine nozzle is about 10ms, in which the sudden rise of the thrust vectoring angle occurs in 1.4ms. After about 12ms, the flow and thrust vectoring angle tend to be stable. The recovery time of the efficient FTV serpentine nozzle does not exceed 10ms, which is about half the time of the thrust vectoring formation. Generally speaking, the dynamic response of the efficient FTV serpentine nozzle can be completed in 20ms, which is faster than that of the conventional mechanical thrust vectoring nozzles, and its thrust vectoring response rate is about 20-50 times that of mechanical ones.