Numerical investigation of the solid particle erosion rate in a steam turbine nozzle

A numerical investigation of solid particle erosion in the nozzle of 300 MW steam turbine is presented. The analysis consists in the application of the discrete phase model, for modelling the solid particles flow, and the Eulerian conservation equations to the continuous phase. The numerical study employs a computational fluid dynamics (CFD) software, based on a finite volume method. The investigation permits us to know the influence of the parameters such as: particle diameter, impact angle, particle velocity and particle distribution on the erosion rate in the surface of the nozzle. These parameters are analyzed to different operational conditions in the turbine. The results show the eroded zone which increases the throat area through the nozzle provoking changes in the operation conditions. When the throat area increases the turbine demands an increase of steam flow to maintain the power supply. On the other hand, it is shown that the solid particles flow cause the most severe the erosion rate whereas the steam mass flow rate is the most sensitive parameter. Finally it is obtained that the erosion rate decreases as the diameter of the particle increases in a nearly linear form.