Publication detail

Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection

RUDOLF, P. LITERA, J. IBARRA BOLANOS, G. ŠTEFAN, D.

Czech title

Ovlivnění vírového proudění v difuzoru vodní turbíny různými způsoby vstřikování vody

English title

Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection

Type

conference paper

Language

en

Original abstract

Vortex rope, which induces substantial pressure pulsations, arises in the draft tube (diffuser) of Francis turbine for off-design operating conditions. Present paper focuses on mitigation of those pulsations using active water jet injection control. Several modifications of the original Susan-Resiga’s idea were proposed. All modifications are driven by manipulation of the shear layer region, which is believed to play important role in swirling flow instability. While some of the methods provide results close to the original one, none of them works in such a wide range. Series of numerical experiments support the idea that the necessary condition for vortex rope pulsation mitigation is increasing the fluid momentum along the draft tube axis.

Czech abstract

Při provozu Francisovy turbíny v mimooptimálním bodu vzniká v sací troubě (difuzoru) vírový cop. Příspěvek se zamžuje na potlačení tohoto jevu využitím vstřikování paprsku vody. Je aplikováno několik modifikací vycházejících z původního řešení prof. Susan-Resigy. Všechny se zaměřují na ovlivnění smykové vrstvy. Ačkoli se některé svým efektem blíží k původnímu řešení, žádné z nich bohužel nepůsobí v tak širokém provozním rozsahu. Provedené numerické experimenty ukazují, že nezvytnou podmínkou pro potlačení pulzací je zvýšení axiální hybnosti v blízkosti osy difuzoru.

English abstract

Vortex rope, which induces substantial pressure pulsations, arises in the draft tube (diffuser) of Francis turbine for off-design operating conditions. Present paper focuses on mitigation of those pulsations using active water jet injection control. Several modifications of the original Susan-Resiga’s idea were proposed. All modifications are driven by manipulation of the shear layer region, which is believed to play important role in swirling flow instability. While some of the methods provide results close to the original one, none of them works in such a wide range. Series of numerical experiments support the idea that the necessary condition for vortex rope pulsation mitigation is increasing the fluid momentum along the draft tube axis.

Keywords in Czech

difuzor; vírové proudění; vstřikování vody; sací trouba

Keywords in English

diffuser; swirling flow; water injection; draft tube

Released

04.06.2018

Publisher

EDP Sciences

ISSN

2100-014X

Book

EPJ Web of Conferences

Pages from–to

1–6

Pages count

6

BIBTEX


@inproceedings{BUT148700,
  author="Pavel {Rudolf} and Jiří {Litera} and Germán Alejandro {Ibarra Bolanos} and David {Štefan},
  title="Manipulation of the swirling flow instability in hydraulic turbine diffuser by different methods of water injection ",
  booktitle="EPJ Web of Conferences",
  year="2018",
  month="June",
  pages="1--6",
  publisher="EDP Sciences",
  issn="2100-014X"
}