Dynamic response of the MICA runner. Experiment and simulation

Abstract

Studying the dynamic response of Francis turbine runners is of paramount importance in order to avoid resonance problems during operating conditions. For this purpose, the natural frequencies as well as their associated mode-shapes and damping ratios of the runner have to be determined. In this paper, an Experimental Modal Analysis (EMA) of the runner of a Francis turbine prototype has been performed. By means of this experimental technique, natural frequencies, mode-shapes and damping ratios have been estimated in air. Results obtained have been compared with a Finite Element Method (FEM) model in order to check the accuracy of the simulation.