Sensitivity study of numerical and geometrical parameters for structural mechanical analyses in the automatic design process of hydraulic machines

Abstract

In the present paper a sensitivity study of numerical and geometrical parameters related to structural mechanical analyses of a hydraulic machine is presented. The sensitivity study is carried out for the blades of two different hydraulic machines, a propeller blade of a submersible vehicle and a runner blade of a kinetic river turbine. The focus of this work is on static structural mechanical analyses, which are performed with the open source finite element program CalculiX. Parameters for the sensitivity study are numerical parameters like the global mesh size as well as the local mesh refinement at certain locations of the blade. Furthermore, the sensitivity of geometrical parameters such as the blade thickness at different locations or the shape of the fillet is investigated. The results of the sensitivity study show that the numerical parameters have a small influence compared to the geometrical parameters. The most dominant geometrical parameter is the blade thickness at the hub. In case of a high load due to the centrifugal force, the influence of the blade thickness at the tip of the blade increases.