Publication result detail

Unsteady Flow in the Draft Tube with Elbow Part B - Numerical Investigation

RUDOLF, P.

Original Title

Unsteady Flow in the Draft Tube with Elbow Part B - Numerical Investigation

English Title

Unsteady Flow in the Draft Tube with Elbow Part B - Numerical Investigation

Type

Paper in proceedings (conference paper)

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.

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.

Key words in English

draft tube, unsteady, vortex, turbulence modeling, helicity

Authors

RUDOLF, P.

RIV year

2011

Released

26.06.2001

Publisher

NTNU Trondheim

Location

Trondheim

Book

Proceedings of IAHR Workgroup Meeting

Pages from

52

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",
  pages="155",
  publisher="NTNU Trondheim",
  address="Trondheim"
}