Experimental Study of Sediment Erosion in Pelton Turbine Bucket

Abstract

In hydroelectric power plants (HPPs), sediment-laden water flows through entire turbines, causing components to be damaged over time. Pelton turbine components serve abrasive erosion from particle hardness, and rough surface when subjected to high flow velocities and various jet impingement angles. In this study, an experiment was conducted to examine the erosion-prone areas of a small-scale Pelton turbine bucket under actual flow conditions. For the experiment, the Pelton bucket was painted with four distinct layers of paint: red, yellow, green, and blue. These layers served as indicators, helping us to visually track the erosion process. The setup was specifically designed to inject sediment upstream of the nozzle. It operated for a significant period of 0- 30 minutes, and every 5 minutes, the erosion pattern was noted with the nozzle fully open at 10 l/s and a net head of 6m with jet impingement angle 75°, 90°, and 105°. After operating for 0-30 minutes in sediment-laden flow conditions, a pattern of erosion was revealed, showing the hot spots (areas more susceptible to erosion) during the investigation at jet angles of 75°, 90°, and 105°. The most severe erosion areas are in the bucket domain, specifically at the splitter region and the deeper upper and lower parts of the brim. The erosion mechanism was influenced by the jet diameter and impingement angle on the bucket splitter. The experiment revealed that the outer regions of the bucket, where the flow was directed outward, suffered the most severe erosion, providing evidence of particle separation at high accelerations.