Abstract

The aim of presented research is to estimate the losses in the flow of steam through the rotor of last stage LP steam turbine. In this case two types of losses may take place, namely aerodynamic (profile, secondary flow, leakage) and thermodynamic (due to the heat addition caused by condensation). In the paper three different calculation models have been compared. The first one is the streamline curvature method (SCM), used on the meridional plane with correlations of losses, and the other are based on the Reynolds averaged Navier-Stokes governing ąuations. The N-S equations for the 3D steam flow are solved using two models for the liquid phase. The first one is an equilibrium dry/wet steam model and the second one is the nonequilibrium model. In this case, the governing equations are coupled with the system of partial differential equations describing the liquid phase. The real gas local equation of state is used calculation of the water-steam properties and thermodynarnic functions. The homogenous nucleation processes in the water steam are modeled using the classical nucleation theory. Flow in the considered case has strong 3-D character and real gas effects are significant, which causes significant losses in the last stages. The results of calculations of the wet steam flow are discussed and compared.