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)"
}