Vlastní ortogonální dekompozice tlakových polí v kuželu savky modelové Francisovy (Tokke) turbíny

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

conference paper

en

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.

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.

vlastní ortogonální dekompozice, POD, OpenFOAM, Fluent, Francisova turbína

POD, CFD, OpenFOAM, Fluent, Francis turbine

2015

06.01.2015

IOP Publishing

1742-6596

Journal of Physics: Conference Series

579

1

1–14

14