Publication detail
Unsteady Flow in the Draft Tube with Elbow Part B - Numerical Investigation
RUDOLF, P.
Czech title
Nestacionární proudění v sací troubě Část B - Numerická simulace
English title
Unsteady Flow in the Draft Tube with Elbow Part B - Numerical Investigation
Type
conference paper
Language
en
Original abstract
The unsteady numerical simulation of the flow in the draft tube was performed in order to find out a suitable flow model being able to predict the precessing vortex core. The CFD code FLUENT was used for this flow analysis. The investigated computational domain corresponds to the Francis turbine draft tube for a runner less operation. The radial and tangential velocities on the radial inlet are simulating the free vortex. The domain is extended to the large tank in order to avoid ill-possed outlet boundary condition. The results have confirmed that RSM turbulence model can predict the origin and behavior of the precessing vortex core in the draft tube. The vortex motion and the precessing frequency can be analyzed. The results of the numerical simulation correspond to the conclusions based on the experimental observation. Finally different definitions for vortex identification are discussed.
Czech abstract
Byla provedena simulace nestacionárního proudění v sací troubě vodní turbíny za účelem nalezení vhodného modelu pro precesní pohyb vírového copu. K analýze byl použit CFD program Fluent. Vyšetřovaná oblast odpovídá Francisově turbíně bez oběžného kola. Výsledky simulace potvrdily, že model Reynoldsových napětí je schopen předpovídat vznik a chování vírového copu. Numerická simulace dobře odpovídá experimentálním výsledkům.
English abstract
The unsteady numerical simulation of the flow in the draft tube was performed in order to find out a suitable flow model being able to predict the precessing vortex core. The CFD code FLUENT was used for this flow analysis. The investigated computational domain corresponds to the Francis turbine draft tube for a runner less operation. The radial and tangential velocities on the radial inlet are simulating the free vortex. The domain is extended to the large tank in order to avoid ill-possed outlet boundary condition. The results have confirmed that RSM turbulence model can predict the origin and behavior of the precessing vortex core in the draft tube. The vortex motion and the precessing frequency can be analyzed. The results of the numerical simulation correspond to the conclusions based on the experimental observation. Finally different definitions for vortex identification are discussed.
Keywords in English
draft tube, unsteady, vortex, turbulence modeling, helicity
Released
26.06.2001
Publisher
NTNU Trondheim
Location
Trondheim
Book
Proceedings of IAHR Workgroup Meeting
Pages count
155
BIBTEX
@inproceedings{BUT3496,
author="Pavel {Rudolf},
title="Unsteady Flow in the Draft Tube with Elbow Part B – Numerical Investigation",
booktitle="Proceedings of IAHR Workgroup Meeting",
year="2001",
month="June",
publisher="NTNU Trondheim",
address="Trondheim"
}