Prediction of losses in the flow through the last stage of low-pressure steam turbine

In this paper, the numerical modelling of the flow through the low-pressure steam turbine last stage was presented. On the basis of predicted wet steam flow-field, the aerodynamic as well as thermodynamic losses were estimated. For calculations of the wet steam steady flow-field three numerical methods were employed. The first method was a streamline curvature method (SCM). The commercial CFD code (CFXTACflow) and an in-house code, both solving the 3-D RANS equations, were the next two methods. In the wet steam region, by means of all three methods, the equilibrium flow was modelled. Additionally, the in-house CFD code was used for modelling of the non-equilibrium steam condensing flow. In this work, the comparison of the cascade loss coefficient for stator and rotor and selected flow parameters for the stage were presented, compared and discussed.