Numerical assessment of parameters influencing the modal response of a Kaplan turbine model

Abstract

The present study intends to investigate numerically the impact of: i) the fluid added mass, ii) the turbine rotational speed and iii) the variation of the runner blade bearing stiffness due to the turbine water head on the modal response of a reduced scale Kaplan turbine. The impact of each variable has been quantified by means of a series of numerical modal analyses of the turbine in vacuum and in water, and at rest and rotating. It has been found that the natural frequencies of the Kaplan turbine model are sensitive to all the variables investigated in the present paper, the added mass being the factor which has the greatest impact.

Dynamic response analysis of a reduced scale Kaplan turbine model operating in propeller mode

“…A preliminary investigation of the turbine modal response had already been carried out both experimentally and numerically to help in the design of the measuring system and to support the analysis of the present results. A detailed description of the rotor and runner modes of vibrations can be found in the previous works of Roig et al [10][11][12].…”

Experimental and numerical modal analysis of a reduced scale Kaplan turbine model

“…Most engineers and researchers currently rely on numerical models to predict the natural frequencies and mode shapes of hydraulic turbines [7][8][9]. However, due to the complexity of these structures, the models usually require calibration through experimental results.…”