Author(s): H. Brekke.
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Keywords: No Keywords
Abstract: The paper is based upon a theoretical and experimental study on oscillatory flow in tunnels and penstock in Electrohydraul ic Power Plants. The frictional damping of oscillations is proven to be a function of the head loss constant, the cross section area of the conduit and the frequency and amplitude of the flow oscillation. The in fluence of the turbine characteristics is also included in the theoretical analysis. Verified by measurements this work proves that even if the Thoma stability criterium for a surge shaft is fulfilled the turbine governin gmay be unstable if the surge shaft is long and/or throttled because waterhammer waves in the main tunnel do not show sufficient decay when passing the surge shaft.
Year: 1985