000263402 001__ 263402
000263402 005__ 20190614161115.0
000263402 022__ $$a0888-3270
000263402 02470 $$a000447480400006$$2isi
000263402 0247_ $$a10.1016/j.ymssp.2018.07.053$$2doi
000263402 037__ $$aARTICLE
000263402 245__ $$aDynamic modal analysis during reduced scale model tests of hydraulic turbines for hydro-acoustic characterization of cavitation flows
000263402 269__ $$a2019-02-15
000263402 260__ $$c2019-02-15
000263402 336__ $$aJournal Articles
000263402 520__ $$aFrancis turbines operating at off-design conditions experience the development of unfavourable cavitation flows in the draft tube at the runner outlet, which induce pressure pulsations and hydro-acoustic resonances in the worst cases. The assessment of hydropower plant units at off-design conditions is possible by means of one-dimensional numerical simulation, which however requires a proper modelling of the draft tube cavitation flow. The corresponding hydro-acoustic parameters can be identified for a wide number of operating points on the reduced scale model of the machine by modal analysis of the hydraulic test rig. This identification approach is efficient but can however be time-consuming for an industrial project. The paper aims at proposing and validating a faster procedure to identify the eigenfrequencies and the corresponding eigenmodes of a hydraulic test rig featuring a reduced scale model of a Francis turbine operating in off-design conditions. The test rig is excited by injecting a periodical discharge with a rotating valve whose frequency linearly increases from 0 to 7 Hz. Based on the response of the test rig, measured by pressure sensors placed along the pipes, the eigenfrequencies and the corresponding eigenmodes are identified for several operating conditions. The hydro-acoustic parameters are then identified by using a one-dimensional numerical model of the test rig. The results are in very good agreement with those obtained with the standard procedure, i.e. with a stepwise increase of the excitation frequency. This new approach represents an important gain of time and might be applied to assess hydropower plant stability in an industrial context. (C) 2018 Elsevier Ltd. All rights reserved.
000263402 650__ $$aEngineering, Mechanical
000263402 650__ $$aEngineering
000263402 6531_ $$afrancis turbine
000263402 6531_ $$acavitation flow
000263402 6531_ $$amodal analysis
000263402 6531_ $$adynamic excitation
000263402 6531_ $$aone-dimensional modelling
000263402 6531_ $$afrancis turbines
000263402 6531_ $$afull load
000263402 700__ $$aFavrel, Arthur$$0245980
000263402 700__ $$g183522$$aGomes Pereira Junior, Joao$$0249112
000263402 700__ $$aLandry, Christian$$0245304
000263402 700__ $$aMueller, Andres
000263402 700__ $$aYamaishi, Kazuhiko
000263402 700__ $$0241012$$aAvellan, Francois
000263402 773__ $$q81-96$$j117$$tMechanical Systems And Signal Processing
000263402 8560_ $$fjoao.gomes@epfl.ch
000263402 909C0 $$mfrancois.avellan@epfl.ch$$0252135$$zMarselli, Béatrice$$xU10309$$pLMH
000263402 909CO $$particle$$ooai:infoscience.epfl.ch:263402$$pSTI
000263402 961__ $$afantin.reichler@epfl.ch
000263402 973__ $$aEPFL$$sPUBLISHED$$rREVIEWED
000263402 981__ $$aoverwrite
000263402 980__ $$aARTICLE