Session: 01-18 Inlets, Nozzles, Mixers and Nacelles III

Paper Number: 126499

126499 - 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. Efficient fluidic vectoring serpentine nozzle not only has the above advantages, but also has simpler structure, lighter weight, and quicker vector response, therefore, it has come into the consideration of exhausting systems all over the world. Remarkably, there are complex pressure gradients and strong swirl characteristics inside the serpentine nozzle, such that efficient fluidic vectoring design of the serpentine nozzle faces greater challenges than conventional nozzles. Therefore, this paper conducts numerical investigation on the efficient fluidic vectoring technology of high pressure ratio serpentine nozzle for larger thrust-to-weight aero-engine. The investigation content covers the working mechanism and flow characteristics of efficient fluidic vectoring serpentine nozzle. On this basis, we continue to carry out study on the dynamic response characteristics of efficient fluidic vectoring serpentine nozzle, thereby obtaining the perturbation propagation of the secondary flow jet in the supersonic mainstream, the flow characteristics during the thrust vectoring formation/recovery process and the time magnitude of the thrust vectoring dynamic response. 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 induced shock wave and a more obvious deflection of the mainstream. Under the condition of high pressure ratio, the time of thrust vectoring formation of efficient fluidic vectoring serpentine nozzle is about 10ms, in which the sudden rise of thrust vectoring angle occurs in 1.4ms. After about 12ms, the flow and thrust vectoring angle tend to be stable. The recovery time of efficient fluidic vectoring serpentine nozzle does not exceed 10ms, which is about half the time of the thrust vectoring formation. The main reason is that the flow of the thrust vectoring recovery process is under favorable pressure gradient, while the flow of the thrust vectoring formation process is under the adverse pressure gradient, and the thrust vectoring formation process has the interaction effect between the separation zone behind the secondary injection and the secondary flow trajectory after the stability of the thrust vectoring. Therefore, it takes a longer time to establish a stable thrust vectoring. Generally speaking, the dynamic response of efficient fluidic vectoring serpentine nozzle can be completed in 20ms, which is faster than that of conventional mechanical thrust vectoring nozzles, and its thrust vectoring response rate is about 20-50 times that of mechanical ones.

Presenting Author: ZhongHao Hui Northwestern Polytechnical University

Presenting Author Biography: Zhonghao Hui is the doctor postgraduate of Northwestern polytechnical University in China, He is mainly engaged in the research of exhaust system of aircraft engine, including serpentine nozzle and thrust vectoring nozzle.

Authors:

Jingwei Shi Northwestern polytechnical University
ZhongHao Hui Northwestern Polytechnical University
Li Zhou Northwestern polytechnical University
Zhanxue Wang Northwestern polytechnical University