Reference measurements on a Francis model turbine with 2D Laser-Doppler-Anemometry

28th IAHR symposium on Hydraulic Machinery and Systems

Frey, A.^1 ; Kirschner, O.^1 ; Riedelbauch, S.^1 ; Jester-Zuerker, R.^1 ; Jung, A.^2

Institute of Fluid Mechanics and Hydraulic Machinery, Pfaffenwaldring 10, Stuttgart

70550, Germany^1

Voith Hydro Holding GmbH and Co. KG, Alexanderstraße 11, Heidenheim a.d. Brenz

89522, Germany^2

关键词: Circumferential velocity;    High resolution;    Measurement planes;    Optical refraction;    Reference measurements;    Rotational frequency;    Velocity components;    Velocity fluctuations;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/49/8/082007/pdf
DOI  :  10.1088/1755-1315/49/8/082007

来源: IOP

【 摘 要 】

To validate the investigations of a high-resolution CFD simulation of a Francis turbine, measurements with 2D Laser-Doppler-Anemometry are carried out. The turbine is operated in part load, where a rotating vortex rope occurs. To validate both, mean velocities and velocity fluctuations, the measurements are classified relative to the vortex rope position. Several acrylic glass windows are installed in the turbine walls such as upstream of the spiral case inlet, in the vaneless space and in the draft tube. The current investigation is focused on a measurement plane below the runner. 2D velocity components are measured on this whole plane by measuring several narrow spaced radial lines. To avoid optical refraction of the laser beam a plan parallel window is inserted in the cone wall. The laser probe is positioned with a 2D traverse system consisting of a circumferential rail and a radial aligned linear traverse. The velocity data are synchronized with the rotational frequency of the rotating vortex rope. The results of one measurement line show the dependency of the axial and circumferential velocities on the vortex rope position.