Research On Design And Aerodynamic Performance For Variable Cycle Engine Rear Bypass Injector

The variable cycle engine is the most advantageous candidate for the fifth generation of aircraft engines,and the rear bypass injector(RVABI)is one of the main regulating components of the variable cycle engine.In this paper,the RVABI design method is established.Then,with the help of CFD numerical simulation,the aerodynamic performance of RVABI is obtained and the parameterization research is also carried out.The suitability of RVABI with the front and rear components is discussed,thus the RVABI aerodynamic performance research system is founded.Firstly,through the summary of the current aircraft engine injector-mixer design method and the variable-cycle engine requirements for injecting-mixing,a design method suitable for the RVABI is built,and based on UG secondary development,the RVABI rapid prototyping platform was built to realize the 3D parametric modeling.The RVABI model was designed on the condition that the design conditions are given,and the obtained model was numerically simulated by CFD method.The aerodynamic performance and flow characteristics under design and off-design conditions were obtained,and the design method's feasibility and rationality was verified.Secondly,the modulating state performance of the RVABI is studied.Based on the design condition model,the scheme of area adjustment of RVABI is established.The RVABI flow field under different area ratios is calculated by CFD method,and the operating state of the adjustment state is obtained.The dynamic variation law of the flow field was analyzed.Thirdly,in order to grasp the influence of geometric parameter changes on its performance,the mixing room profile configuration,mixing room length and central body configuration are taken as the research variables,and the aerodynamic performance of the feasibility and rationality is studied parametrically.And the impact of flow characteristics provides support data for further optimization of the design.Finally,in order to achieve synergy in variable cycle engines,the matching performance of RVABI and the front and rear components was studied.Firstly,the adjustment state calculations are carried out for different critical operating conditions of RVABI,the performance parameters of the adjustment state in the whole working range are obtained,so that the working characteristic map is established.Then,through the analysis of the working mode of the double external bypass engine,the matching scheme between the RVABI and the adjacent components is established.And the matching characteristics of the working points of RVABI selected in this paper are analyzed.The ability of the designed RVABI to work with adjacent components was verified.