Etude du champ instationnaire de vitesse en sortie de roue de turbine. Etude expérimentale et numérique

The experimental and numerical study of the non stationary velocity field at the exit of a turbine runner

Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Machines Hydrauliques

Abstract

An experimental and numerical analysis of the velocity and pressure fields at the exit of a FRANCIS turbine runner is proposed. LDV flow survey, pressures and wall friction measurements, are analyzed using phase average techniques, to analyze the influence of the rotation and the passage of the blade wakes. These measurements permit to characterize the turbulence in this zone (tensor of REYNOLDS) with the pressure fluctuations. The non stationary flow is modeled on the basis of a RANS code with a k ~ ε closure. The comparisons between calculations and experiments permit to underline several imperfections of this non stationary turbulent modeling.