NEW APPROACH TO THE NUMERICAL ANALYSIS OF THE SWIRL WATER TURBINE AND EXPERIMENTAL VERIFICATION

This paper is focused on the nonlinear analysis of the dynamic behavior of a fluid-structure interaction. The innovative mathematical model presented here includes a new type of boundary condition and allows modal analysis and the steady state or the unsteady responses. Our new method is based on the determination of boundary condition by defining special convolutory integrals for the fluid velocity and the pressure and their expansion into the series of eigenmodes of a structure vibration, This approach allows the separation of the structure and the fluid from each other. We applied this method to analyze the modal behavior of a swirl turbine, using the ANSYS and FLUENT program systems. The added mass, damping coefficients were calculated as influence of a fluid and structure interaction. These added effects were combined with an elastic rotor system, Several experimental investigations were made in parallel to the calculation models. The computational analyses and the experimental results show relatively good agreement. Our calculation method can find many technical applications, e.g. the solution of blades or rotors vibrations in centrifugal pumps or water turbines.