Author(s): Roman Klasinc; Andrej Predin

Linked Author(s): Roman Klasinc

Keywords: Horizontal shaft turbine model; Draft tube; Emergency gate; Vertical gatevibration; Model to prototype transfer

Abstract: The static and dynamic behaviour of an emergency gate situated downstream of a horizontal-shaft turbine was studied on a physical model. The static behaviour of the gate was transferred to prototype conditions using Froude’s law of similitude. The analysis and transfer of the dynamic movements of the gate, however, turned out to be much more complex than expected. In particular, we studied the behaviour of the emergency gate for the case of disconnection of the power unit from the system or breakdown of the guide vane system. We used analytical methods both in the time domain and in the frequency domain (FFT, correlation analysis). The evaluation of the experimental data showed that several vibration modes could be distinguished depending on the gate opening. Natural vibrations characterised a first zone, corresponding to relatively small gate openings. As the gate opening increased, the vibration behaviour of the gate became increasingly dependent on the swirl pulsations of the turbine. The experimental data was verified using mathematical models. Finally, the data was transferred from the model to the prototype by use of the law of dynamic similitude. This allowed guidelines to be prepared for the dynamic dimensioning of the prototype gate.

DOI:

Year: 1999