Publications de Christophe Nicolet

Hydroacoustic modelling and numerical simulation of unsteady operation of hydroelectric systems

Hydropower represented in 1999 19% of the world electricity production and the absolute production is expected to grow considerably during the next 30 years. Francis turbines play a major role in the hydroelectric production due to their extended range of ...

EPFL2007

Methodology for Risk Assessment of Part Load Resonance in Francis Turbine Power Plant

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

At low flow rate operation, Francis turbines feature a cavitating vortex rope in the draft tube resulting from the swirling flow of the runner outlet. The unsteady pressure field related to the precession of the vortex rope induces plane wave propagating i ...

2006

Simulation tool linking hydroelectric production sites and electrical networks

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

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

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 ...

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

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

Hydroacoustic 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 ...

2006

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