American Society of Civil Engineers

Hydro Turbine Submergence

by James L. Gordon, (Monenco Consultants Ltd, Canada)

pp. 1365-1374

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Document type: Conference Proceeding Paper
Part of: Waterpower ’89
Abstract: The elevation of a hydro-electric turbine above or below tailwater is based on hydraulic model studies to determine the critical sigma, defined as the ratio of barometric pressure plus submergence depth at which cavitation commences, all divided by the rated head. An analysis of more than 80 existing turbines, has shown that turbine setting is a function of the turbine throat velocity head, the number of runner blades and the atmospheric pressure. Submergence Equations are developed for horizontal or vertical axis Kaplan, propeller and Francis units, along with equations for determining turbine throat diameter based on the desired setting.

ASCE Subject Headings:
Head (fluid mechanics)
Hydraulic models
Hydro power
Model studies
Tail water

Author Keywords:
Hydraulic Turbines
Atmospheric Pressure and Density - Cavitation - Hydraulics--Analysis - Hydroelectric Power Plants
Critical Sigma - Submergence Equations - Tailwater Elevation - Turbine Setting - Turbine Throat Diameter