Increasing the fatigue strength and operational reliability of the critical elements of a steam turbine

Abstract

The article has dealt with the possibility of increasing the fatigue strength and operational reliability of the critical elements of the flow part of a steam turbine – multi-supporting roots of working blades – using technological and structural measures. Investigation of the stress state of а three-supporting mushroom root by means of а software package based on the finite element method showed that it is advisable to increase the radius of curvature at the support surfaces to reduce the local irregularity distribution of stresses in the concentrator zones. The analysis of the results was carried out using the Neuber formula for effective stress concentration coefficients, taking into account the geometry of the profile and the material properties of the structure. Recommendations are proposed to improve the work of the blade roots taking into account the peculiarities of its stress state and the nature of the damage in operation. The results of the work can be used in the field of power engineering, in the design and operation of steam turbines.