Hydro-acoustic resonance behavior in presence of a precessing vortex rope: observation of a lock-in phenomenon at part load Francis turbine operation
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Hydraulic machine design can now take advantage of advanced flow calculation methods which are made available by several CFD software companies. Thanks to these recent developments, the so called "Volume Of Fluid" (VOF) methods can be now used for the anal ...
International Association For Hydraulic Research1998
The two techniques, vibratory monitoring and pit counting, show promising results for the prediction of prototype cavitation erosion from model tests of Francis turbines. These cavitation detection methods are compared in two set-ups at different power lev ...
International Association For Hydraulic Research1994
This paper presents similitude laws for steady-oscillatory phenomena associated with the off-design operation of Francis turbines. An appropriate procedure is proposed for stability of operation tests to be performed along with standard model tests. The el ...
International Association For Hydraulic Research1994
High load surging is a specially delicate side of Francis turbines' dynamic behavior. There is yet no sure method to predict the occurrence of pulsations on a full-size machine, either from model test results or theoretical analysis. Upon commissioning of ...
International Association For Hydraulic Research1992
An original validation of the vibratory approach of the cavitation erosion monitoring is presented. Cavitation induced vibrations on a given blade of a large hydro turbine are compared to vibrations induced at the lower guide bearing as well as to the pres ...
The setting level of a hydraulic machine, specially for low head machines, is decided with respect to the possible alteration of the efficiency due to the cavity development. This alteration can easily be noticed by following the evolution of the efficienc ...
Three dimensional numerical tools are now commonly used in the design or analysis process of the internai flow of hydraulic machinery. As an illustration of the use of such tools to study the internai flow of a Francis turbine, the computational results ob ...
International Association For Hydraulic Research1994
An experimental study of flow in a Francis hydraulic turbine, especially designed for the GAMM Workshop, has been carried out. In order to provide a data base for the validation and comparison of computational fluid dynamics codes, a Francis turbine mode! ...
Stability of operation of Francis turbines Hydraulic disturbances often come with the operation of Francis turbines outside of design head and flow. In some cases, the excessive amplitude of the dynamic system response to these disturbances leads to res ...
Experimental studies have shown that outlet cavitation of a Francis turbine is influenced by the active nuclei content of the test loop water, up to a limit curve called the saturation characteristic. To determine the importance of this influence in operat ...
International Association For Hydraulic Research1992
