Life Damage Evaluation of 600MW Supercritical Condensing Steam Turbine Rotor under Start-up Schedule

In order to achieve accurate life damage evolution of steam turbine rotor, it was significant to proposed a empirical model by utilizing the finite element analysis combined with the CDM (Continuum Damage Mechanics) model. The finite element analysis was utilized for calculating the maximum stress during the start-up schedule. Linear and nonlinear CDM frameworks were adopted for assessing the creep-fatigue damage of steam turbine rotor, which was corresponded to the failure criteria of ASME (American Society of Mechanical Engineers) Section III. The analysis revealed that the 600MW supercritical condensing steam turbine rotor exhibited temperatures and peak stresses of 535.26°C and 381.25 MPa respectively during start-up, as calculated via finite element analysis. The 600MW supercritical condensing steam turbine rotor demonstrated low-cycle fatigue durability of 1087 cycles and creep rupture life of 1.5006×10 6 hours under start-up conditions. For the application in current paper assumption, the lifespan of 600MW supercritical condensing steam turbine rotor under start-up schedule is 90 years and 100 years by nonlinear CDM model and linear CDM model respectively according to failure criterion of ASME section III, which is illustrated the nonlinear CDM results are more conservative and safer. The research results of this paper can be applied to the evaluation of the lifespan of steam turbine rotors in thermal power plants, as well as the development of online monitoring systems for lifespan and digital twin systems, which is significant in field of power system modeling, simulation and analysis.