Vibration of Water Turbine when Air is admitted to its Draft Tube : Experimental Study

抄録

Our experimental study revealed that the severest vibrations in the draft tube of water turbines can be eliminated or greatly reduced by the admission of air into the draft tube, but unless just the right amount of air is admitted, instead of reducing vibration, a large amount of draft head is destroyed, and, conversely, vibrations are increased. To verify this fact, we used models of draft tubes. We obtained the relations among amplitude of vibration, flow ratio of air to water, draft tube efficiency, and ratio of circulatory component to axial component of water. Here the optimum amount of water to be admitted is studied and results are presented graphically.