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Background
Sediment erosion in Francis turbine components
Design of test setup
Sediment erosion of turbine components has been a challenge for the hydro power plants
under Himalayan and Andes basins. In Francis turbines, sediment erosion also causes
increase of clearance between guide vanes and facing plates and cross flow occurs from the
increased gap. This cross flow together with other secondary flows disturbs the velocity
profile at the runner inlet. Change in velocity profile at the inlet causes additional erosion
damage and other undesired effects in turbine runner. Examination of effects of increased
cross flow from guide vanes on the flow conditions at the runner inlet will be main aim of this
study.
Objectives
1. Study of causes and effects of erosion in Francis turbine operating in sediment flow.
2. Develop a test setup to create the flow conditions between guide vanes and runner inlet
of a high head Francis turbine.
3. Investigate the effects of leakage flow around the guide vanes of high head Francis
turbines on velocity distribution at the runner inlet.
PhD Thesis
Waterpower Laboratory
Sediment Erosion in
Hydraulic Turbines
By Biraj Singh Thapa
Supervisor: Ole Gunnar Dahlhaug