Numerical assessment of stress concentration in Francis runner blade — crown/band junctions

Abstract

The paper presents the results of numerical investigation for stress distribution near runner blade-crown/band junctions. Starting with the geometrical investigation of the geometries for a real turbine, different junction geometries were identified. Eight different junction geometries were numerically investigated in order to determine the stress distribution. The applied load for structural analysis was the pressure distribution, obtained from a Computational Fluid Dynamics analysis of the runner blade. The results of the stress distribution will allow to quantify the effect of different junction geometry on stress concentration and integrity of the runner.