Rotordynamics of the Turbomachinery Coupled to a Pump-Turbine Runner

Introduction

The behavior of a pump-turbine is influenced not only by the flow around it but also by the structural behavior of the whole machinery coupled to it. Moreover the coupling between the runner and the electrical part cannot accurately be made without considering the behavior of the mechanical components placed inbetween. Accounting for the rotordynamic of the entire turbomachinery from the pump-turbine runner to the electrical rotor is crucial to link accurately the hydraulic and electric part. Since the present computational ressources are not powerfull enough to simulate strong Fluid-Structure Interaction of the runner, other alternative method must be used to be able to build a global model of the entire turbomachinery coupled to a pump-turbine runner.

Doctoral student : Steven Roth

Objectives

The aim of the thesis is to build an accurate model of the entire turbomachinery allowing to take into account the influence of the hydrodynamic phenomenon on the electric side and vice versa. The use of state of art Fluid-Structure Interaction tools will allow to determine added mass, damping and stiffness of the runner. An accurate model of the entire turbomachinery can then be build based on these hydrodynamic parameters. The influence of rotor stator interaction on the rotordynamic behavior of the turbomachinery will be investigated. The flow behavior around the runner will be analyzed when reaching critical rotating speed.