Development of expression for resistance to erosion by solid particles in turbine blades

Abstract

The application of reliability centered maintenance onrepairable equipment requires that the reliability calculation should not to be based on failure statistics, as in traditional methods, but rather on its condition. The "load vs resistance" method presumesthe comparison of process parameters with carefully selected mechanical properties of the materials. The author proposes the calculation based on parameters monitored for diagnosis purposes. Specifically, he analyzes the erosion of steam turbine bladessubject tothe action of solid particle from the superheaters, which, under certain conditions, grow to critical thicknesses and due to stresssactionscaused by thermal changes, fracture and detach, acquiring such energy that then impacts the surface of the blades causing theirerosion. These phenomena are analyzed and equations are established in relation withthe mechanical properties of the blade metal , with the energy requird by oxide flakes to cause their erosion. An expression has been obtained, allowing for the application of the method, whichd has not been found in analyzed research works.