The Thermal Stress of a Domestic 300MW Steam Turbo Unit during its Startup and Shutdown

Abstract

The simulation system on the thermal stress of the rotor during startup & shutdown for a domestic 300MW steam turbo unit, by the simulation, the surface of the shaft was suffered a crushing stress, but it was a pulling stress when a unit shutdown. The max thermal stress & the max combined stress produced on the rotor of a medium pressure cylinder was about 16% bigger than those on the rotor of the high pressure cylinder when they had the same increase rate of temperature. When thought from economics & safety, the optimal temperature-increase-rate of the rotor was 1.6°C/min when the unit startup at cold state, but it was 1. 8°C/min when started up and shut down the unit at hot state, it’s optimal for slipping-parameter and the optimal temperature-decease-rate of the rotor was 0.85°C/min.