Study On Modeling And Simulation Of Split-shaft Gas Turbine

Gas turbine, which is also known as rotating impeller-type heatengine, is a type of internal combustion power machinery. Its impellersare driven by a continuous flow of gas to obtain high-speed rotation. As aresult， the fuel energy is converted to useful work. Gas turbines arewidely used in aviation, ships and power plant systems, so it has practicalvalue to study their performance through modeling and simulation.Matlab/Simulink is the integration of a graphical object-orientedmodular modeling and visual simulation technology, so it is suitable to beused as platform for ground gas turbine model simulation. In this paper,by Split-shaft gas turbine functional analysis, a gas turbine modelsimulation platform is set up in Matlab/Simulink simulation environmentthrough modular modeling method，and thus achieving the steady anddynamic simulation of a certain type of ground Split-shaft gas turbine andverifying the validity of the simulation platform.Based on the Monod and the Logistic model，this paper proposes anew empirical model for fitting the gas turbine compressor performancecurve and uses differential evolution algorithm to identify the parameters.Fitting results show that the new model can deal with the nonlinearcharacteristics of compressor performance curve and achieve higheraccuracy comparing with the existing method.In steady-state simulation, several typical component modules of gasturbine including inlet compressor, combustor, high-pressure turbine andpower turbine are established by using Simulink module library.Steady-state equations module is established according to the flowbalance and power balance relations in gas turbine. Taking account intothe nonlinear characteristics of the steady-state equations, Newton-Raphson method is adopted as the solver. Finally equilibrium point of thesteady-state operation is obtained, thereby the steady-state simulation is completed.In the dynamic-state simulation, the impact of the specific heat andgas-oil ratio are considered and volume inertia method is used to achievedynamic simulation. A rotor dynamics module and two volume dynamicsmodules are added to the simulation platform, and non-iterative solutionframework is established based on the volume of inertial effects, thusrealizing dynamic-state simulation of Split-shaft gas turbine model.In the gas turbine controller design, PI controller parameter is tunedby using differential evolution algorithm, and the simulation results showthat the system with the proposed PI parameter tuning method can havegood dynamic characteristics.The simulation model established on the basis of theabove-mentioned method is relatively simple, clear and of goodscalability, while enjoying high simulation efficiency and accuracy. So itis a useful research for modeling and simulation of gas turbine.