Erosion of Pelton buckets and changes in turbine efficiency measured in the HPP Fieschertal

28th IAHR symposium on Hydraulic Machinery and Systems

Abgottspon, A.^1 ; Staubli, T.^1 ; Felix, D.^2

Competence Center for Fluid Mechanics and Hydro Machines (CC FMHM), Hochschule Luzern (HSLU), Technikumstrasse 21, Horw

CH-6048, Switzerland^1

Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Hönggerbergring 26, Zurich

CH-8093, Switzerland^2

关键词: Abrasive erosion;    Coating thickness;    Design discharge;    Geometrical changes;    Horizontal axis;    Progressive damage;    Repeated measurements;    Turbine efficiency;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/49/12/122008/pdf
DOI  :  10.1088/1755-1315/49/12/122008

来源: IOP

【 摘 要 】

Geometrical changes and material loss of Pelton turbine runners as well as changes in turbine efficiency were measured at HPP Fieschertal in Valais, Switzerland. The HPP is equipped with two horizontal axis Pelton units, with each 32 MW nominal power, 7.5 m3/s design discharge, 515 m head and two injectors. The injectors and the buckets are hard-coated. Hydro-abrasive erosion was quantified based on repeated measurements on two runner buckets using (i) 3d-scanning and (ii) a coating thickness gauge. Changes in efficiency were measured by applying the sliding needle procedure. In addition to these periodically performed measurements, efficiency was also continuously monitored. The highest erosion rate was measured during the first half of the sediment season 2012 including a major sediment transport event. Because the runner was not fully reconditioned at the beginning of this season, progressive damages occurred. After the event, a splitter width of 10 mm was measured, corresponding to 1.5 % of the inner bucket width. The cut-outs were eroded by up to 9 mm towards the axis. The efficiency reductions ranged from 1 % in the year with the major sediment transport event to insignificant differences in 2014, when the sediment load was small and only little hydro-abrasive erosion occurred.