Proper Orthogonal Decomposition of Pressure Fields in a Draft Tube Cone of the Francis (Tokke) Turbine Model

Loading...
Thumbnail Image
Date
2015-01-06
ORCID
Advisor
Referee
Mark
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Publishing
Altmetrics
Abstract
The simulations of high head Francis turbine model (Tokke) are performed for three operating conditions - Part Load, Best Efficiency Point (BEP) and Full Load using software Ansys Fluent R15 and alternatively OpenFOAM 2.2.2. For both solvers the simulations employ Realizable k-epsilon turbulence model. The unsteady pressure pulsations of pressure signal from two monitoring points situated in the draft tube cone and one behind the guide vanes are evaluated for all three operating conditions in order to compare frequencies and amplitudes with the experimental results. The computed velocity fields are compared with the experimental ones using LDA measurements in two locations situated in the draft tube cone. The proper orthogonal decomposition (POD) is applied on a longitudinal slice through the draft tube cone. The unsteady static pressure fields are decomposed and a spatio-temporal behavior of modes is correlated with amplitude-frequency results obtained from the pressure signal in monitoring points. The main application of POD is to describe which modes are related to an interaction between rotor (turbine runner) and stator (spiral casing and guide vanes) and cause dynamic flow behavior in the draft tube. The numerically computed efficiency is correlated with the experimental one in order to verify the simulation accuracy.
Článek se zabývá CFD simulací modelu vysokospádové Francisovy turbíny (Tokke) s využitím dvou spftware, komerční ANSYS Fluent a nekomerční OpenFOAM. Je provedeno vyhodnocení integrálních hydraulické účinnosti, spádu, kroutícího mementu atd. pro tři různé provozní body. Dále je provedena POD analýza tlakového pole řezem kužele savky. Srovnány jsou rychlsotní profily v savce z LDA měření s numerickým výpočtem a tlakové pulzace v savce a v mezeře mezi rozvaděčem a oběžným kolem. Závěrem je porovnána shoda mezi experimentálním měřením a CFD výpočty.
Description
Citation
Journal of Physics: Conference Series. 2015, vol. 579, issue 1, p. 1-14.
http://iopscience.iop.org/1742-6596/579/1/012002/
Document type
Peer-reviewed
Document version
Published version
Date of access to the full text
Language of document
en
Study field
Comittee
Date of acceptance
Defence
Result of defence
Document licence
(C) IOP Publishing
Citace PRO