Publication detail

Model of Pressure Pulsations in Hydraulic Turbine Draft Tube Based on Linearized

RUDOLF, P. POCHYLÝ, F. HABÁN, V.

Czech title

Model tlakových pulzací v sací troubě vodní turbíny založený na linerizované Rayleigh-Plessetově rovnici

English title

Model of Pressure Pulsations in Hydraulic Turbine Draft Tube Based on Linearized

Type

conference paper

Language

en

Original abstract

Vortex rope appears in hydraulic turbine draft tube for partial load operation. This rope can, for certain sigma values, cavitate and contain saturated water vapour. Cavitating vortex rope is cause of pressure pulsations and effects dynamics of the whole turbine unit. Time behaviour of the spherical cavitating bubble is described by well-known Rayleigh-Plesset equation. This contribution presents derivation of the Rayleigh-Plesset equation for infinitely long cylindrical cavity imitating vortex rope. Linearized form of this equation accompanied by continuity equation and force equillibrium equation create basis for transfer matrix of the draft tube with cavitating vortex rope. Paper discusses ideas, steps of the derivation, but also necessary assumptions and simplifications leading to this new model. The final transfer matrix includes effect of the vortex rope volume change and can be included into the system of transfer matrices describing behaviour of the turbine unit with penstock.

Czech abstract

Pro jisté hodnoty čísla sigma se objevuje v sací troubě kavitující vírový cop, který způsobuje tlakové pulzace a ovlivňuje dynamiku stroje. Je odvozena Rayleigh-Plessetova rovnice pro válcový kavitující vírový cop. Rovnice je posléze linearizována a vytvořena přenosová matice sací trouby s kavitujícím vírovým copem. Tato matice může být začleněna do systému přenosových matic celého soustrojí.

English abstract

Vortex rope appears in hydraulic turbine draft tube for partial load operation. This rope can, for certain sigma values, cavitate and contain saturated water vapour. Cavitating vortex rope is cause of pressure pulsations and effects dynamics of the whole turbine unit. Time behaviour of the spherical cavitating bubble is described by well-known Rayleigh-Plesset equation. This contribution presents derivation of the Rayleigh-Plesset equation for infinitely long cylindrical cavity imitating vortex rope. Linearized form of this equation accompanied by continuity equation and force equillibrium equation create basis for transfer matrix of the draft tube with cavitating vortex rope. Paper discusses ideas, steps of the derivation, but also necessary assumptions and simplifications leading to this new model. The final transfer matrix includes effect of the vortex rope volume change and can be included into the system of transfer matrices describing behaviour of the turbine unit with penstock.

Keywords in English

draft tube problems, machine dynamics behaviour

RIV year

2006

Released

28.06.2006

Publisher

UPC Barcelona

Location

Barcelona (Spain)

Book

Proceeding of Abstracts IAHR Int. Meeting of the Work Group on Cavitation and Dynamics Problems in Hydraulic Machinery and Systems.

Pages count

45

BIBTEX


@inproceedings{BUT24555,
  author="Pavel {Rudolf} and František {Pochylý} and Vladimír {Habán},
  title="Model of Pressure Pulsations in Hydraulic Turbine Draft Tube Based on Linearized",
  booktitle="Proceeding of Abstracts IAHR Int. Meeting of the Work Group on Cavitation and Dynamics Problems in Hydraulic Machinery and Systems.",
  year="2006",
  month="June",
  publisher="UPC Barcelona",
  address="Barcelona (Spain)"
}