A study on performance of aero-engine with fluidic thrust vector nozzle

Shock Vector Controlling (SVC) nozzle is one of the most effective ways to obtain the thrust vector for the advanced engine. The SVC nozzle has the advantages of simple structure, light weight and fast response. Numerous analytical, numerical and experimental studies have been carried out on SVC nozzle in recent years. While these studies mainly focus on the nozzle and ignore the influence between SVC nozzle and engine. In fact, the secondary flows of fluidic thrust vectoring nozzle are all extracted from the engine fan or high pressure compressor, no matter it is based on SVC or others. The extraction and injection of the secondary flow both influence the components matching and engine performance. And the mass flow and pressure of secondary flow are constrained by engine working condition in turn. So the SVC nozzle should be installed in the engine environment for evaluation. The influence of SVC nozzle secondary flow on engine thermodynamic cycle and performance is in two major ways. First, when the secondary flow extracts from the fan or HPC, the operating point of the engine will change. It results in the thermodynamic parameters at each engine stations and the performance of engine change. The reason for this change is that the bleeding of secondary flow broke the mass flow balance equations between the engine components. Second, the injection of secondary flow in the expansion section of nozzle also leads to engine performance change, while the engine operating point remains normal. The characteristic of certain SVC nozzle is obtained by computational fluid dynamics method. Then the Response Surface Method (RSM) model based on the design of experiment is employed to build the relations of performance parameters and design variables of SVC nozzle. Combining basic engine performance simulation model with SVC nozzle RSM model, the model for engine with SVC nozzle is built. To evaluate the performance of the engine with SVC nozzle, the conceptual design of double bypass variable cycle engine with SVC nozzle is given. The influence of the secondary flow extracting from the fan outlet, CDFS outlet and the first stage of HPC is discussed. And its performances such as vector angle, thrust coefficient, thrust and specific fuel consumption are obtained by employing the engine simulation model built by this paper.