Pressure Fluctuations and Fatigue Stresses in Storage Pumps and Pump-Turbines

Similarity is shown between a model and a full scale pump or pump-turbine in the static and dynamic fields of stress and in the vibration characteristics, if the peripheral speed of rotation and the material used for the blades are the same for the two machines. Simple formulas are derived for predicting phase coincidence of the pressure fluctuations caused by the blade passage of the runner rotating in a diffuser. Test results are shown which confirm the established theory. This work was made as part of a joint development work on pump-turbine by Sulzer Brothers, Ltd., and English Electric Company.