Self-Excited Vibration of a Hydraulic Turbine

Abstract

Severe vibration of a hydraulic turbine was found to be self-excited. Vibration at the natural frequency when operating at synchronous speed produced self-sustaining whirl of the shaft. Gyroscopic action of the turbine runner caused the vibration to be self-excited. Admission of relatively small amounts of compressed air to the region between the headcover baffle plate and the crown of the runner stopped the vibration by preventing buildup of a rotating pressure field.