Real-time Evaluation Method of Turbine Rotor's Thermal Stress with Governing Stage Partial Admission Condition at Low-Load

In order to ensure the safety and stability of the new energy power system, many power units will be maintained at low-load state for a long time during peak-load regulation in China. However, the partial arc admission of the nozzle governing mode will cause uneven temperature distribution in the circumferential direction after GS, which will affect real-time thermal stress of the rotor. Toward this end, this paper proposes a real-time evaluation method of thermal stress for rotors in low-load conditions. First of all, the solution boundary conditions of thermal stress model can be obtained by designing the measuring points arrangement after GS, which comprehensively takes into account the uneven temperature distribution of GS under low-load conditions. In the meantime, various punching schemes are analyzed by ANSYS, which used to analyze the influence of cylinder structure strength caused by the new measuring point punching of each scheme. The result shows that the punching impact on the stress and deformation of cylinder is not obvious, which has a great significance to reduce minimum technical output and improve peak governing capability of thermal power unit.