Jean-Louis Kueny

Flow in a Pelton Turbine Bucket: Numerical and Experimental Investigations

The flow model used for the numerical simulations is based on the generalized homogeneous multiphase flow model developed by Ishii 15, with the additional sources of momentum for the effects of the Coriolis and centrifugal accelerations in a steady rotating frame of reference. The governing equations are described below

Numerical Analysis of Flow Phenomena Related to the Unstable Energy-Discharge Characteristic of a Pump-Turbine in Pump Mode

Regions of positive slope in the pressure-discharge characteristics are one of the major concerns in design and operation of centrifugal pumps, as they are limiting the admissible operating range to values above the critical discharge. The industrial pump turbine of specific speed ν=0.42 (nq=66 min-1) proposed as QNET-CFD test case TA6-04 shows a marked saddle in the energy-discharge characteristic associated to a sudden drop of efficiency versus discharge at part load. The pump-turbine consists of a shrouded impeller with five blades, a diffuser with 22 guide and stay vanes and a spiral casing. CFD flow simulations on a reduced model were carried out with a finite volume Navier-Stokes code (CFX-5.7) using block- tructured hexahedral meshes and the Menter-SST Turbulence model. Control of numerical quality has been performed. Reduced models with relatively low computational effort (mixing plane interface) already permit to capture the drop in efficiency and energy coefficient to analyze the flow phenomena inducing the drop of the energy coefficient Ψ that occurs at partial discharge. Analysis of local flow patterns and energy and velocity distributions at the rotor-stator interface that are related to the onset of recirculation are presented.

Werlé–Legendre Separation in a Hydraulic Machine Draft Tube

The three-dimensional turbulent flow in a compact hydraulic machine elbow draft tube is numerically investigated for several operating conditions, covering an extended range around the best efficiency point. Comparisons with the experimental data are presented as validation. The interest is focused on the experimentally observed pressure recovery drop occurring near the best efficiency point. The flow is first analyzed locally by means of a topological analysis, then globally with an energetic approach. The study provides evidence for the role played by a Werle-Legendre separation originating in the bend. The separation is due to the contrasting flow angles imposed by the blades, and the angle resulting from the secondary flow

Werlé-Legendre Separation in a Hydraulic Machine Draft Tube

Note: Using Smart Source Parsing 14-18 3 Reference LMH-CONF-2002-015View record in Web of Science Record created on 2005-11-04, modified on 2017-05-10

A Three Dimensional Spiral Casing Navier-Stokes Flow Simulation

Navier-Stokes flow simulations are now commonly used in the process of hydraulic turbomachinery design. Comparison with experiments and careful understanding of the behavior of such tools is however very important to the correct interpretation of the results. Following this trend, Navier-Stokes flow simulations, using three solvers, applied to a pump turbine spiral casing in turbine mode, are presented and discussed in this paper.