Fluid exciting force due to flutter and rotor-stator interactions in axial flow turbines

29th IAHR Symposium on Hydraulic Machinery and Systems

Ajiro, K.^1 ; Matsuda, K.^1 ; Onishi, K.^1 ; Mineshima, T.^1 ; Miyagawa, K.^2

Department of Applied Mechanics, Waseda University, Tokyo

1690072, Japan^1

Department of Applied Mechanics and Aerospace Engineering, Waseda University, Tokyo

1690072, Japan^2

关键词: Axial flow turbines;    Exciting forces;    FEM (finite element method);    Hydraulic machines;    Pressure fluctuation;    Reynolds Averaged Navier-Stokes Equations;    Rotor-stator interactions;    Self-excited vibrations;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/240/2/022061/pdf
DOI  :  10.1088/1755-1315/240/2/022061

来源: IOP

【 摘 要 】

In recent years, the size and the speed of axial flow type hydraulic turbines have been continuously increased, leading to an increase of the fluid exciting forces due to rotor-stator interactions in hydraulic machines featuring both rotor and stator. In addition, the use of composite material for the blades of large hydraulic machines is increasingly investigated. Such flexible and lightweight hydrofoils can however easily experience self-excited vibration such as flutter effect. Fluid exciting forces generated in hydraulic machines might cause resonance, fatigue of the blade and finally damage. This paper aims to evaluate fluid exciting forces produced by rotor-stator interactions in axial flow turbines and the hydro-elastic response to the flutter of a flexible hydrofoil. To evaluate fluid exciting forces due to rotor-stator interactions, experiments are carried out using a closed-loop water channel featuring an axial flow turbine. The pressure distribution on the blade surface and the influence of axial distance between rotor and stator on the pressure fluctuations amplitude on the blade surface are investigated. A good agreement between experimental and numerical values is found. Regarding the flutter effect, FSI (Fluid Structure Interaction) simulation of one hydrofoil coupling RANS (Reynolds-averaged Navier-Stokes equations) and FEM (Finite Element Method) simulation is carried out to study the three-dimensional behaviour of the flutter.