Coupled CFD and Thermal Steady State Analysis of Steam Turbine Secondary Flow Path

The main purpose of this work is to conduct coupled CFD analysis of the steam flow in the secondary part of turbine and study thermal rotor/stator steady state. We consider a 11 stage high-pressure cylinder of a power steam turbine with extended terminal labyrinths. Domain of interest is only the secondary flow path of the cylinder, therefore the shroud and blades are beyond the scope of this work. All blades are virtually removed and on the imaginary cylindrical surface the effective boundary conditions are assigned. This takes into account heat fluxes that came to disks/diaphragms from blades in reality. Practical engineering method of obtaining axi-symmetric solution has been developed and results are presented and discussed. Thermal state analysis shows a significant influence of secondary steam bleeding on temperature distribution of rotor and stator.