The acceleration and mode transition performance are two significant performances of Adaptive Cycle Engine (ACE). However, separating the processes of acceleration and mode transition will slow down the response speed of thrust. Therefore, this paper proposes a multi-mode acceleration optimization control method that simultaneously performs ACE acceleration and mode transition. Firstly, an ACE component model with inlet flow characteristics was established, and the performance before and after mode transition were analyzed. Secondly, the principle of ACE acceleration optimization was analyzed, and the Front Variable Area Bypass Injector (FVABI) and Mode Selection Valve (MSV) were adopted in the acceleration process. Finally, based on the Sequential Quadratic Programming (SQP) algorithm, considering the degradation effects of engine components, we optimize the acceleration control plan for fuel and variable geometry mechanisms. The simulation results show that at the subsonic cruise point, the ACE multi-mode acceleration optimization control method can shorten the acceleration time from idle to middle state by 30.33%, and accelerate the thrust response speed by 33.72%. When the compressor flow rate of ACE deteriorates by 2% and the high-pressure turbine efficiency deteriorates by 4%, the adaptive acceleration control plan increases the high-pressure speed by 2.13% and thrust by about 6.82%; within the flight envelope, the acceleration time is reduced by more than 25%, and the thrust response speed is increased by more than 20%.

Traditional centralized Proportional Integral (PI) controller design methods based on Equivalent Transfer Functions (ETFs) have poor decoupling effect in turboprop engines. In this paper, a centralized PI design method based on dynamic imaginary matrix and equivalent transfer function is proposed. Firstly, a method for solving equivalent transfer functions based on the dynamic imaginary matrix is proposed, which adopts dynamic imaginary matrix to describe the dynamic characteristics of the system, and obtains the equivalent transfer function based on the dynamic imaginary matrix characteristics. Secondly, for the equivalent transfer function, a centralized PI control gain is designed using the Taylor expansion method. Meanwhile, this paper further proves that the centralized PI design method proposed in this paper has integral stability. Considering the impact of altitude and Mach number on turboprop engines, a linear feedforward control method based on the transfer function matrix is further proposed based on the centralized PI controller, and the stability of the entire comprehensive control method is proved. Finally, to ensure the safe and effective operation of the turboprop engine, a temperature and torque limiting protection controller is designed for the turboprop engine. Simulation results show that the centralized PI controller design method and linear feedforward control method proposed can effectively improve the control quality of turboprop engine control systems.

Inlet and engine matching is the premise of stable, efficient and economic work of the whole propulsion system. In this paper, the matching problem between the inlet and the engine of the adaptive cycle engine is studied, and use of the special FLADE (Fan on Blade) components of the adaptive cycle engine to achieve the inlet and engine matching in the subsonic/supersonic cruise missions is proposed. Firstly, according to the matching principle of the inlet and engine, this paper analyzes the flow characteristics of the supersonic inlet and the role of FLADE components, and develops an integrated mathematical model of the supersonic inlet/adaptive cycle engine. Secondly, the altitude and speed characteristics of the engine with the open and closed FLADE guide vanes are studied. Combined with the subsonic/supersonic cruise mission requirements of the fighter, the capture area and throat area of the adaptive cycle engine inlet are designed, and the matching between the inlet and the engine is realized. Finally, simulation is carried out at the sub/supersonic cruise task points of the engine. The results show that opening the FLADE guide vane swallowing overflow at the subsonic cruise point can move the working point of the inlet from the subcritical to critical state, reducing the fuel consumption of the propulsion system by 10.5% and the installation loss by 1%. At the supersonic cruise point, to meet the matching characteristics of the inlet and the engine as well as the engine installation thrust requirements, it is necessary to close the FLADE guide vane to increase the unit thrust of the propulsion system.

To study the change mechanism and the control of the variable cycle engine in the process of modal transition, a variable cycle engine model based on component level characteristics is established. The two-dimensional CFD technology is used to simulate the influence of mode selection valve rotation on the engine flow field, which improves the accuracy of the model. Furthermore, the constant flow control plan is proposed in the modal transition process to reduce the engine installed drag. The constant flow control plan adopts the augmentation linear quadratic regulator control method. Simulation results indicate that the control method is able to effectively control the bypass ratio and demand flow of the variable cycle engine, and make the engine transform smoothly, which ensures the stable operation of the engine in modal transition and the constant demand flow of the engine.

Aimed at the problem of instability in engine control caused by vector deflection in experiment of turbofan engines with Axisymmetric Vectoring Exhaust Nozzle (AVEN), a vector deflection stability control method of aero-engine based on Linear Active Disturbance Rejection Control (LADRC) is proposed. Firstly, based on CFD numerical simulation, aerodynamic performance model of AVEN is established, and the aerodynamic load change rule of the nozzle throat area actuator during vector deflection is revealed. Subsequently, the integrated model of AVEN/turbofan engine is established by Simulink/AMESim co-simulation. Finally, the nozzle throat area control loop based on LADRC is designed. The simulation results show that the integrated model can reflect the influence of vector deflection on the stability of the control system. The accuracy comparison between the fan rotor speed and the test data during vector deflection is larger than 1%, indicating a high degree of confidence. Compared with the conventional PID control, the designed LADRC control loop reduces the speed of the low-pressure rotor during vector deflection by 70%, which effectively improves the control stability of the vector deflection. Meanwhile, the fuel flow ratechange during the vector deflection process is smaller and more economical, which provides an important reference for engineering applications.