English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Unstable guide vane torsional mode self-excited vibrations that occur at small guide vane openings during the transient operations with pump flow, such as the starting and closing of the pump mode, are considered to have potentially severe consequences, such as guide vane slippage or damage to the link and lever mechanism. Related site tests have indicated that the end wall clearance of a guide vane may have important influences on torsional mode self-excited vibrations. In this paper, numerical investigations, which were based on computational fluid dynamics (CFD) with a single degree of freedom (1DOF) mass-spring oscillator, were carried out on a prototype high-head reversible pump turbine. The results showed that the guide vane self-excited vibrations are unstable under steady-state conditions and during the pump mode’s starting up process for cases with small end wall clearances. In addition, the critical conditions of self-excitation instability under steady-state conditions have larger safety margins than those during the pump mode’s starting up process. After further discussion, it was concluded that increasing the end wall clearance to suppress unstable guide vane self-excited vibration is unreliable due to the complexity and randomness of the initial vibration excitations.

journal of marine science and engineering

Influence of End Wall Clearance on Guide Vane Self-Excited Vibrations at Small Openings during Pump Mode’s Starting Up Process of a Reversible Pump Turbine