Recherche

Afficher tous les résultats pour

Accueil

Personne

François Avellan

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (218)

Numerical simulation of fluid added mass effect on a francis turbine runner

François Avellan, Mohamed Farhat, Eduard Egusquiza

In this paper, a numerical simulation to analyze the influence of the surrounding water in a turbine runner has been carried out using finite element method (FEM). First, the sensitivity of the FEM model on the element shape and mesh density has been analy ...

2007

2D Oscillating Hydrofoil

François Avellan, Mohamed Farhat, Philippe Ausoni, Cécile Münch-Alligné

This paper presents a validation of numerical simulations in case of a forced oscillating hydrofoil. As a representative case study for vibrating blade in hydraulics machines, a 2D NACA 0009 oscillating hydrofoil is considered. Pressure coefficients from e ...

2007

Unsteady CFD Prediction of von Kármán Vortex Shedding in Hydraulic Turbine Stay Vanes

François Avellan, Mohamed Farhat, Philippe Ausoni

All hydraulic turbines containing a casing with stay vanes face the potential dynamic problem of stay vane von Kármán vortex shedding. For hydraulic efficiency purposes the stay vanes tend to be relatively slender in the direction normal to the flow thus b ...

2007

High-Order Modeling of Hydraulic Power Plant in Islanded Power Network

François Avellan, Basile Kawkabani, Jean-Jacques Simond, Philippe Allenbach, Christophe Nicolet, Bob Greiveldinger

Numerical simulations of the transient operation of an islanded power network subject to load rejections are performed. The islanded power network case study consists of a 1-GW hydroelectric power plant featuring four generating units, a long penstock, and ...

IEEE Institute of Electrical and Electronics Engineers2007

Unsteady Numerical Simulations of the Flow Related to the Unstable Energy-Discharge Characteristic of a Medium Specific Speed Double Suction Pump

François Avellan, Philippe Dupont, Olivier Braun

Regions of positive slope in the pressure-discharge characteristics can result in a reduction or even lack of damping of system instabilities. They are therefore one of the major concerns in design and operation of centrifugal pumps as they are limiting th ...

2007

Dynamics and Intensity of Erosive Partial Cavitation

François Avellan, Mohamed Farhat, Eduard Egusquiza

An experimental work has been carried out to investigate the dynamic behavior and the intensity of erosive partial cavitation on a 2-D hydrofoil. Both sheet (stable) and cloud (unstable) cavitation have been tested in a cavitation tunnel for various free s ...

2007

Modeling and Numerical Simulation of a Complete Hydroelectric Production Site

François Avellan, Jean-Jacques Simond, Philippe Allenbach, Christophe Nicolet

For many years the EPFL Laboratory for Electrical Machines develops SIMSEN, a numerical software package for the simulation in transient and steady-state conditions of electrical power systems and adjustable speed drives, having an arbitrary topology. SIMS ...

2007

Rotor-Stator Interaction Induced Pressure Fluctuations: CFD and Hydroacoustic Simulations in the Stationary Components of a Multistage Centrifugal Pump

François Avellan, Philippe Dupont, Mohamed Farhat, Stefan Berten

In a centrifugal pump the interaction between the rotating impeller pressure field and the stationary diffuser pressure field yields pressure fluctuations as the result of a modulation process. These fluctuations may induce hydroacoustic pressure fluctuati ...

2007

Hydrofoil Roughness Effects on von Kármán Vortex Shedding

François Avellan, Mohamed Farhat, Philippe Ausoni

The shedding process of the von Kármán vortices is shown to be highly related to the state of the boundary layer over the entire hydrofoil: The selected hydrofoil has a laminar-turbulent boundary layer transition at mid-chord for an incidence angle of 0° a ...

2007

On the Hydroelectric Stability of an Islanded Power Network

François Avellan, Jean-Jacques Simond, Philippe Allenbach

slanded power networks comprising a small number of large power plants are subject to perturbations leading to important transients, and, hence need high performance governors. The design of these governors requires a detailed model of the system. This is ...

2006

Flow in a Pelton Turbine Bucket: Numerical and Experimental Investigations

Alexandre Perrig, François Avellan, Mohamed Farhat

The aim of the paper is to present the results of investigations conducted on the free surface flow in a Pelton turbine model bucket. Unsteady numerical simulations, based on the two-phase homogeneous model, are performed together with wall pressure measur ...

2006

On the Hydroelectric Stability of an Islanded Power Network

François Avellan, Jean-Jacques Simond, Philippe Allenbach, Christophe Nicolet, Bob Greiveldinger

Islanded power networks comprising a small number of large power plants are subject to perturbations leading to important transients, and, hence need high performance governors. The design of these governors requires a detailed model of the system. This is ...

2006

Modal Response of Hydraulic Turbine Runners

François Avellan, Eduard Egusquiza

The mechanical design of hydraulic turbines is conditioned by the dynamic response of the runner that is usually estimated by a computational model. Nevertheless, the runner has complex boundary conditions that are difficult to include in the computational ...

International Association For Hydraulic Research2006

Pump-Turbine Rotor-Stator Interactions in Generating Mode: Pressure Fluctuation in Distributor Channel

François Avellan, Mohamed Farhat, Amirreza Zobeiri

Investigation of the rotor-stator interactions of a reduced-scale model 0.19 ν= pump-turbine in generating mode is presented for the maximum discharge operating condition. This operating point is chosen in order to have the most important rotor-stator inte ...

International Association For Hydraulic Research2006

Overload Surge Event in a Pumped-Storage Power Plant

François Avellan, Christophe Nicolet

At full load, pump-turbines operating in generating mode may experience a cylindrical cavitation vortex rope caused by the swirling flow in the draft tube cone. Under certain conditions, this vortex rope initiates both pressure and power oscillations. The ...

International Association For Hydraulic Research2006

Tool Path Generation and Post-Processor Issues in Five-Axis High Speed Machining of Hydro Turbine Blades

François Avellan, Christophe Tournier

This paper deals with 5-axis milling of hydraulic blades. The issue developed is essentially linked to problems due to the transition from 3 to 5 axes. A specific attention is done to the Inverse Kinematics Transformation (IKT) which can be source of incoh ...

2006

Experimental investigation of added mass effects on a Francis turbine runner in still water

François Avellan, Eduard Egusquiza

2006

Numerical Simulation and Analysis of Swirling Flow in the Draft Tube Cone of a Francis Turbine

François Avellan

The paper presents numerical investigations of decelerated swirling flows specific to hydraulic turbines draft tube cone, within the framework of axisymmetric flow models. First, we investigate the behaviour of a Burgers vortex in a diffuser as the swirl i ...

International Association For Hydraulic Research2006

Kármán vortex shedding in the wake of a 2D hydrofoil: Measurement and numerical simulation

François Avellan, Mohamed Farhat, Philippe Ausoni, Youcef Ait Bouziad

The present study deals with the shedding process of the Kármán vortices at the trailing edge of a 2D hydrofoil at high Reynolds numbers. Investigations are performed in order to evaluate the ability of an unsteady numerical simulation to accurately reprod ...

2006

One-Dimensional Modeling of Rotor Stator Interaction in Francis Pump-Turbine

François Avellan, Christophe Nicolet, Nicolas Ruchonnet

A one-dimensional hydroacoustic model is set up to perform the numerical simulation of the rotor-stator interaction of a Francis pump-turbine scaled model. The numerical results enable to identify both rotating diametrical modes in the vaneless gap between ...

International Association For Hydraulic Research2006

Page 10 sur 11