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dc.contributor.authorLi, Deyou
dc.contributor.authorWang, Hongjie
dc.contributor.authorChen, Jinxia
dc.contributor.authorNielsen, Torbjørn Kristian
dc.contributor.authorQin, Daqing
dc.contributor.authorWei, Xianzhu
dc.date.accessioned2020-06-09T06:57:18Z
dc.date.available2020-06-09T06:57:18Z
dc.date.created2016-11-09T11:10:25Z
dc.date.issued2016
dc.identifier.issn1996-1073
dc.identifier.urihttps://hdl.handle.net/11250/2657262
dc.description.abstractThe hump feature is one of the major instabilities in pump-turbines. When pump-turbines operate in the hump region, strong noise and serious fluctuations can be observed, which are harmful to their safe and stable operation and can even destroy the whole unit as well as water conveyance system. In this paper, a low specific speed (nq = 36.1 min−1) pump-turbine model was experimentally investigated. Firstly, the hump characteristic was obtained under 19 mm guide vane opening conditions. More interestingly, when the hump characteristic was measured in two directions (increasing and decreasing the discharge), characteristic hysteresis was found in the hump region. The analysis of performance characteristics reveals that the hump instability is the result of Euler momentum and hydraulic losses, and different Euler momentum and hydraulic losses in the two development processes lead to the hysteresis phenomenon. Then, 12 pressure sensors were mounted in the different parts of the pump-turbine model to obtain the time and frequency characteristics. The analysis of the corresponding fast Fourier transform confirms that the hump characteristic is related to low-frequency (0.04–0.15 times rotational frequency) vortices. The occurrence and cessation of vortices depend on the operating condition and measurement direction, which contribute to the hysteresis feature. Finally, the type of the low-frequency vortices was analyzed through the cross power spectrum.en_US
dc.language.isoengen_US
dc.publisherMDPIen_US
dc.rightsNavngivelse 4.0 Internasjonal*
dc.rights.urihttp://creativecommons.org/licenses/by/4.0/deed.no*
dc.titleHysteresis characteristic in the hump region of a pump-turbine modelen_US
dc.typePeer revieweden_US
dc.typeJournal articleen_US
dc.description.versionpublishedVersionen_US
dc.source.volume9en_US
dc.source.journalEnergiesen_US
dc.source.issue8en_US
dc.identifier.doi10.3390/en9080620
dc.identifier.cristin1398662
dc.description.localcode© 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).en_US
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode1


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