H级重型燃气轮机建模与动态仿真

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

采用面向对象的模块化建模方法,建立了一种非线性的H级单轴重型燃气轮机动态仿真模型.为了提高仿真精度,考虑了燃气组分变化和比热容变化对模型精度的影响.通过在Simulink平台上的仿真实验,探讨了外界扰动下H级重型燃气轮机的动态特性以及转子转动惯量对燃气轮机动态特性的影响.结果表明:额定工况下运行的燃气轮机负荷扰动越大,转速和燃料量的超调量越大,但不同负荷扰动过程的调整时间几乎相等;当环境温度升高时,转子转速先上升后下降,燃料量则先下降后上升,稳态时透平排气质量流量减少,排气温度略有上升.在燃气轮机甩负荷过程中,转子的转动惯量越小,转速和燃料量的超调量越大,调整时间越短;转子的转动惯量越大,对负荷扰动的鲁棒性越强;燃气轮机的转轴布置存在最佳方案,采用带3S离合器的单轴布置方案时,燃气轮机的动态特性较好,系统的稳定性较强.

A nonlinear dynamic simulation model was built for the H-class heavy-duty gas turbine using ob- ject-oriented modularized technique. To improve the simulation accuracy, the effects of different gas com- positions 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 condi- tions, 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 increa- ses 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 per- formance of gas turbine would be relatively good and the stability of the system would be relatively high.