Vol. 7, Issue 2, Part B (2025)

Reducing the start-up period with a limitation of the turbine rotor stress has connections with the economical efficiency of equipments and the rotor life, and is a highly nonlinear problem which has multiple local optima. An off-design calculation model was proposed including heat calculation and thermal system theory, based on the model a specific program was developed with VC. Various cold start-up schedules were composed according to the operation regulation of 210MW steam turbine. For each schedule, steam parameters on the main parts of rotor were calculated by the program. They were the reference data for calculating of temperature and stress field for rotor with FEM (finite element method). The results of FEM were used as sample data for SVM (support vector machines). SVM was employed to build the regression model for the start-up schedule and to determine the stresses at the dangerous points. The optimal start-up parameters could be obtained by GA (genetic algorithm). The results show that the fatigue lifetime was increased by 20%, due to the 1.4% reduction of maximum Von-Mises stress, and the start-up period of the optimized schedule was reduced by 124min compared with the original schedule. The optimized start-up schedule was verified by FEM, and the maximum Von Mises stresses at the dangerous points satisfy the requirement.