Publications related to Analysis of large scale hydrodynamic phenomena in turbine draft tubes

One-Dimensional Analysis of Full Load Draft Tube Surge

François Avellan, Mohamed Farhat, Christophe Nicolet

One-dimensional stability analysis of a hydraulic system composed of a penstock, a runner, and a draft tube was carried out to determine the cause of the full load draft tube surge. It is assumed that the cavity volume at the runner exit is a function of t ...

2008

Liquid–liquid two-phaseflow patterns andmasstransfer characteristics inrectangular glassmicroreactors

Albert Renken, Lioubov Kiwi, Anne-Laure Dessimoz

The flow of two immiscible fluids was investigated in rectangular glass microchannels with equivalent diameters of 269 and 400

\mu m

. Deionised water, dyed toluene and hexane were selected as probe fluids. Flow patterns were obtained for Y- and T-junction ...

2008

Aerated flows on stepped chutes with macro-roughness elements, Part II : Energy dissipation

Anton Schleiss, Stéphanie Joëlle André

An experimental research of flow on different systems of stepped overlays for 18.6 degrees and 30 degrees slopes was conducted. In addition to define flow characteristics (Part I), the study highlighted the existence of an homogeneous aerated flow in which ...

2008

Analysis of the Cavitating Draft Tube Vortex in a Francis Turbine Using Particle Image Velocimetry Measurements in Two-Phase Flow

François Avellan, Monica Iliescu

Partial flow rate operation of hydroturbines with constant pitch blades causes complex unstable cavitating flow in the diffuser cone. A particle image velocimetry (PIV) system allows investigating the flow velocity field in the case of a developing cavitat ...

2008

Improvement of Acoustic Doppler Velocimetry in steady and unsteady turbulent open-channel flows by means of seeding with hydrogen bubbles

Anton Schleiss, Giovanni De Cesare, Koen Blanckaert, Tobias Meile

Velocimetry is used in various fields of research. In hydraulics, Ultrasonic Velocimetry based on the Doppler Shift effect can accurately resolve the quasi-instantaneous flow field [Takeda Y. Velocity profile measurement by Ultrasonic Doppler method. Exper ...

Elsevier2008

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

Hydroacoustic modelling and numerical simulation of unsteady operation of hydroelectric systems

Christophe Nicolet

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

Hydrodynamics of the free surface flow in Pelton turbine buckets

Alexandre Perrig

The design of Pelton turbines has always been more difficult than that of reaction turbines, and their performances lower. Indeed, the Pelton turbines combine 4 types of flows: (i) confined, steady-state flow in the piping systems and injector, (ii) free w ...

EPFL2007

Instrumentation development for wall shear-stress applications in 3D complex flows

Elena Berca

In the turbomachines field, friction losses are intensively studied due to their important influence in the overall efficiency of the machine. The parameter helping in quantifying these friction losses is the wall shear-stress. Its role is essential for th ...

EPFL2007

Existence and features of similarity solutions for non-Boussinesq gravity currents

Christophe Ancey, Steve Cochard, Martin Rentschler, Sébastien Wiederseiner

In this paper, the flow dynamics of gravity currents on a horizontal plane is investigated from a theoretical point of view by seeking similarity solutions. The current is generated by unleashing a varying volume of heavy fluid within an ambient fluid of m ...

2007

Analysis of large scale hydrodynamic phenomena in turbine draft tubes

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One-Dimensional Analysis of Full Load Draft Tube Surge

Liquid–liquid two-phaseflow patterns andmasstransfer characteristics inrectangular glassmicroreactors

Aerated flows on stepped chutes with macro-roughness elements, Part II : Energy dissipation

Analysis of the Cavitating Draft Tube Vortex in a Francis Turbine Using Particle Image Velocimetry Measurements in Two-Phase Flow

Improvement of Acoustic Doppler Velocimetry in steady and unsteady turbulent open-channel flows by means of seeding with hydrogen bubbles

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

Hydroacoustic modelling and numerical simulation of unsteady operation of hydroelectric systems

Hydrodynamics of the free surface flow in Pelton turbine buckets

Instrumentation development for wall shear-stress applications in 3D complex flows

Existence and features of similarity solutions for non-Boussinesq gravity currents

Liquid–liquid two-phaseflow patterns andmasstransfer characteristics inrectangular glassmicroreactors

Hydroacoustic modelling and numerical simulation of unsteady operation of hydroelectric systems

Instrumentation development for wall shear-stress applications in 3D complex flows

One-Dimensional Analysis of Full Load Draft Tube Surge

Improvement of Acoustic Doppler Velocimetry in steady and unsteady turbulent open-channel flows by means of seeding with hydrogen bubbles

Existence and features of similarity solutions for non-Boussinesq gravity currents

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

Aerated flows on stepped chutes with macro-roughness elements, Part II : Energy dissipation

Hydrodynamics of the free surface flow in Pelton turbine buckets

Analysis of the Cavitating Draft Tube Vortex in a Francis Turbine Using Particle Image Velocimetry Measurements in Two-Phase Flow