Publication detail
Spatio-temporal description of the swirling flow in hydraulic turbine draft tube
RUDOLF, P. ŠTEFAN, D.
Czech title
Časově-prostorový popis proudění v sací troubě vodní turbíny
English title
Spatio-temporal description of the swirling flow in hydraulic turbine draft tube
Type
conference paper
Language
en
Original abstract
Highly swirling flow leaves runner of the hydraulic turbine, which is operated off the best efficiency point. Instability of the swirling flow results in so called vortex rope. Rotating vortex rope is a source of pressure pulsations, causes structural loads, vibrations and noise. Proper orthogonal decomposition (POD) provides a spatio-temporal description of the draft tube swirling flow and proves that only a very limited number of the flow eigenmodes is necessary to describe the flow dynamics. Construction of the reduced order model (ROM), which is derived by projection of Navier-Stokes equation onto POD basis forms a suitable state equation for the draft tube flow control. Paper presents review of POD application to draft tube flows and proposal of extension to ROM and closed loop flow control.
Czech abstract
Při provozu vodní turbíny v mimooptimálním provozním bodu opouští oběžné kolo silně zavířené proudění. Nestabilita zavířeného proudění pak vede ke vzniku vírového copu, která je zdrojem tlakových pulzací, vibrací a hluku. Vlastní ortogonální dekompozice (proper orthogonal decomposition, POD) nabízí redukci takového tpu proudění do několika vlastních tvarů. Na jejich základě lze pak sestrojit tzv. redukovaný model (ROM), který je výsledkem projekce vlastních tvarů na Navier-Stokesovu rovnici. Výsledná soustava obyčejných diferenciálních rovnic pak může sloužit pro řízení proudění v sací troubě a vytvoření uzavřené řídící smyčky.
English abstract
Highly swirling flow leaves runner of the hydraulic turbine, which is operated off the best efficiency point. Instability of the swirling flow results in so called vortex rope. Rotating vortex rope is a source of pressure pulsations, causes structural loads, vibrations and noise. Proper orthogonal decomposition (POD) provides a spatio-temporal description of the draft tube swirling flow and proves that only a very limited number of the flow eigenmodes is necessary to describe the flow dynamics. Construction of the reduced order model (ROM), which is derived by projection of Navier-Stokes equation onto POD basis forms a suitable state equation for the draft tube flow control. Paper presents review of POD application to draft tube flows and proposal of extension to ROM and closed loop flow control.
Keywords in Czech
sací trouba, vírový cop, POD, ROM
Keywords in English
draft tube, vortex rope, POD, ROM, control
RIV year
2014
Released
26.11.2014
Publisher
TU Wien
Location
Vienna
ISBN
978-3-9501937-9-4
Book
Proceedings of 18th International Seminar on Hydropower
Pages from–to
191–201
Pages count
10
BIBTEX
@inproceedings{BUT111329,
author="Pavel {Rudolf} and David {Štefan},
title="Spatio-temporal description of the swirling flow in hydraulic turbine draft tube",
booktitle="Proceedings of 18th International Seminar on Hydropower",
year="2014",
month="November",
pages="191--201",
publisher="TU Wien",
address="Vienna",
isbn="978-3-9501937-9-4"
}