Modeling And Simulation Study On Gas Turbine

Gas Turbine Generator Unit has many advantages such as high efficiency, rapid start, short building cycle, low investment and little environmental pollution, and it can meet the requirements of sustainable development of energy industry, so its application in our country electric power is strengthened. However, it is difficult to master its actual work process because of the highly nonlinear characteristic of Gas Turbine Generator Unit. To resolve this problem, built its simulation model, which has important significance and can be used to predict the dynamic characteristics of Gas Turbine system and study the problem in the process of operation and designing.This paper takes single shaft gas turbine as the research object, studies on the modeling and simulation. On the basis of analyzing the structure and characteristic of unit, the mathematical model of gas turbine system is built and dynamic characteristics are researched by simulation experiment. The main contributions of the paper are as follows:â‘ The mathematical model of gas turbine system are obtained, including the models of compressor, combustion chamber, gas turbine and rotor. Fuzzy identification is used to fit the characteristic curve of air compressor. The model of combustion chamber is established on the basis of material balance, thermal balance and pressure balance. The model of gas turbine is built according to the thermodynamic principle. In addition, selection of type of load, cooling air flow rate, the calculation of mechanical loss and the enthalpy of flue gas are considered in the model of gas turbine system.â‘¡It is difficult to describe the characteristic of air compressor by accurate mathematical model because of its special background, working conditions and highly nonlinear characteristic. The input data is clustered by the entropy method and competitive learning algorithm, the identification of the input parameter is ascertained by the least-squares algorithm and the fuzzy rule model. The identification model is practical,not only has high precision but also gets a linear mathematical model. It enables the fitting method of the air compressor characteristic to become simple.â‘¢Based on the model of gas turbine system, the dynamic simulation experiments with step disturbances of fuel flow rate, load, the opening degree of inlet guide vanes and inlet temperature are carried out, and the main dynamic characteristics of unit are analyzed. The dynamic characteristics of unit under control effect with step disturbance of load, the opening degree of inlet guide vanes and inlet temperature are also analyzed, and the validity of the simulation model is verified.Moreover, the simulation model established in the paper is also considered the different relationship of enthalpy and temperature of fuel gas with the fuel components, and the subroutine procedure which can be calculated enthalpy and temperature of fuel gas under different fuel components is built. Therefore, this simulation model can be used for different gas turbine system when inputting different characteristic data of air compressor, the main dynamic characteristics of single shaft gas turbine system can be examined and analyzed by this model, and it also can be used as a subsystem on the gas - steam combined cycle system.