Theoretical and Numerical Analysis of the Mechanical Erosion in Steam Turbine Blades. Part II

F Rueda Martínez,J A Ortega Herrera,A A Rueda Martínez,M Toledo Velázquez,I Carvajal Mariscal,J Abugaber Francis,G Polupan

doi:10.4236/epe.2011.33030

Abstract

In the low pressure section of the steam turbines the damages are pronounced becoming remarkable in all the stages, since the generation of water liquid microparticles implies the impact on the blades having majors problems of erosion in the last stages by the increase of the humidity. In the first part of this work, the calculation presented of the transonic velocity field for the stream frictionless and the drops in the flow line, on the basis of the frictionless, two-dimensional, stationary, transonic and homogenous flow, give an approximate movement of the droplets and its accumulation on the stator blades, flowing through the steam. In order to understand the causes that originate the erosion on the blades of the last stages in low pressure section of steam turbines, the previous procedure is developed in a code in Fortran and the obtained results of velocity distribution in the output of blades that have flow conditions of wet steam are presented.

Highlights

In blade cascades the saturated steam flows is a nebula of droplets
In the low pressure section of the steam turbines the damages are pronounced becoming remarkable in all the stages, since the generation of water liquid microparticles implies the impact on the blades having majors problems of erosion in the last stages by the increase of the humidity
In order to understand the causes that originate the erosion on the blades of the last stages in low pressure section of steam turbines, the previous procedure is developed in a code in Fortran and the obtained results of velocity distribution in the output of blades that have flow conditions of wet steam are presented

Summary

Introduction

In blade cascades the saturated steam flows is a nebula of droplets. Due to the accumulation that is formed on the stator blade, the erosion features in the following rotor blades is the consequence. The impact of droplets on the blade surfaces is essentially based in the range of particles with sizes affected by the forces of inertia. These droplets cannot follow the path of the steam flow in the blade cascade. In turbines the water becomes to escape from the stator blades in form of large drops, generally toward the suction side of the following rotor blade, causing there erosion problems

Methods

Results

Conclusion