Experimental Study of Transient Flow Regimes in a Model Hydroturbine Draft Tube

Swirling flow with the formation of a precessing vortex core (PVC) in the draft tube model of a hydroturbine was studied. Experiments were performed on an aerodynamic setup under transient operating conditions of the hydroturbine. The turbine operating conditions were varied by continuously changing...

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Bibliographic Details
Published in:Energies (Basel) 2021-03, Vol.14 (5), p.1240
Main Authors: Litvinov, Ivan, Suslov, Daniil, Gorelikov, Evgeny, Shtork, Sergey
Format: Article
Language:English
Subjects:
acoustic sensors
draft tube
laser-Doppler anemometer
phase (conditional) averaging
precessing vortex core
transient regime
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Summary:Swirling flow with the formation of a precessing vortex core (PVC) in the draft tube model of a hydroturbine was studied. Experiments were performed on an aerodynamic setup under transient operating conditions of the hydroturbine. The turbine operating conditions were varied by continuously changing the flow rate at a constant runner speed. The transition from the partial load regime, when a precessing vortex core is formed, to the best efficiency point without a core is considered. Applied to this task, a comparison of the windowed Fourier transform with wavelet analysis is given. The dependence of the PVC lifetime in the transient regime correlates with the transient time. It is shown that the velocity profiles and the spectrum of pressure pulsations in transient regimes change quasistatically between part-load operation and the best efficiency point of the turbine. The phase-averaged velocity distributions in the transient regimes show that a transient regime is a sequence of quasisteady regimes.
ISSN:1996-1073
1996-1073
DOI:10.3390/en14051240