Transient Thermoelastic Analysis of a Steam Turbine During its Start-up from the Cold State

Thermodynamic, thermal and strength calculations of the steam turbine in unsteady states were performed for a steam turbine heat-up from the cold state. These calculations were made for a given geometry of the turbine outer casing, inner casing, stator blade carriers, rotor and elements of the turbine heat-up system as well as for given parameters of the steam supplied to turbine inlet/exit pipes and given heat-and-flow balance at crucial turbine flow sections. The objective of this calculation was to analyze of the displacements over time of the turbine outer casing, inner casing, blade carriers, balance piston gland and outer shaft glands, and rotor of the steam turbine during the cold start-up. The heat fluxes at the outer casing, inner casing, and blade carriers, balance piston gland and outer shaft gland were calculated using the FLUENT code. These heat fluxes were applied to turbine elements for structure computations. The FE model of the steam turbine was prepared in the ANSYS code. The global and relative expansions and distortions of the casing as well as the maximal stress distribution over a time are of special interest. The numerical calculations were compared with the measurements of casing and shaft deformation. In many cases the numerical points agree well with the measurement points.