000148339 001__ 148339
000148339 005__ 20190316234800.0
000148339 0247_ $$2doi$$a10.1115/1.4001486
000148339 022__ $$a0098-2202
000148339 02470 $$2ISI$$a000277744700002
000148339 037__ $$aARTICLE
000148339 245__ $$aAnalysis and Prevention of Vortex Breakdown in the Simplified Discharge Cone of a Francis Turbine
000148339 269__ $$a2010
000148339 260__ $$bAmerican Society of Mechanical Engineers$$c2010
000148339 336__ $$aJournal Articles
000148339 520__ $$aWe perform a numerical analysis of the decelerated swirling flow into the discharge cone of a model Francis turbine operated at variable discharge and constant head, using an axisymmetric turbulent swirling flow model and a corresponding simplified computational domain. Inlet boundary conditions correspond to velocity and turbulent kinetic energy profiles measured downstream the Francis runner. Our numerical results are validated against experimental data on a survey section further downstream in the cone, showing that the Reynolds stress turbulence model with a quadratic pressure-strain term correctly captures the flow field. It is shown that the diffuser performance quickly deteriorates as the turbine discharge decreases, due to the occurrence and development of vortex breakdown, with a central quasistagnant region. We investigate a novel flow control technique, which uses a water jet injected from the runner crown tip along the axis. It is shown that the jet discharge can be optimized for minimum overall losses, while the vortex breakdown is eliminated. This flow control method is useful for mitigating the Francis turbine flow instabilities when operating at partial discharge.
000148339 6531_ $$aTurbulent Swirling Flows
000148339 6531_ $$aConical Diffusers
000148339 6531_ $$aNumerical-Simulation
000148339 6531_ $$aKappa-Epsilon
000148339 6531_ $$aPrediction
000148339 6531_ $$aSystems
000148339 6531_ $$aModels
000148339 700__ $$aSusan-Resiga, Romeo
000148339 700__ $$aMuntean, Sebastian
000148339 700__ $$0243100$$g176678$$aHasmatuchi, Vlad
000148339 700__ $$aAnton, Ioan
000148339 700__ $$aAvellan, François$$g104417$$0241012
000148339 773__ $$j132$$tTransactions- American Society of Mechanical Engineers Journal of Fluids Engineering$$k5
000148339 8564_ $$uhttps://infoscience.epfl.ch/record/148339/files/2011%20Resiga%20APM8184%20Mathematical%20modelling%20of%20swirling%20flow%20in%20hydraulic%20turbines.pdf$$zPublisher's version$$s718012$$yPublisher's version
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000148339 917Z8 $$x176678
000148339 917Z8 $$x176678
000148339 917Z8 $$x176678
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000148339 937__ $$aEPFL-ARTICLE-148339
000148339 973__ $$rREVIEWED$$sPUBLISHED$$aOTHER
000148339 980__ $$aARTICLE