Modeling and Dynamic Simulation of H-class Heavy-duty Gas Turbines

A nonlinear dynamic simulation model was built for the H-class heavy-duty gas turbine using object-oriented modularized technique. To improve the simulation accuracy, the effects of different gas compositions and specific heat capacities on the accuracy of the model were considered. Through simulations on the Simulink platform, the dynamic characteristics of H-class heavy-duty gas turbines were studied under external disturbances and different moments of inertia on the rotor. Results show that under rated conditions, the larger the load distrubance is, the greater the over adjustment of rotational speed and fuel mass flow will be, but the adjustment time in different load disturbance processes is nearly the same. When the ambient temperature increases, the rotational speed first increases and then declines while the fuel mass flow first declines and then increases; the exhaust gas flow decreases and the exhaust temperature increases slightly during steady state operation of the turbine. In the process of gas turbine load rejection, the smaller the moment of inertia on rotor is, the greater the over adjustment of rotational speed/fuel mass flow and the shorter adjustment time will be; whereas, the greater the moment of inertial on rotor is, the stronger robustness will be resulted against load disturbance. There exists an optimum scheme of gas turbine shaft arrangement; when the single shaft arrangement with 3S clutch is adopted, the dynamic performance of gas turbine would be relatively good and the stability of the system would be relatively high.