Parametric Modeling of Pelton Bucket and the effect of the bucket depth on sediment erosion

Nepal has a huge potential in hydropower, where Pelton turbines have emerged as a preferred choice due to high-head mountainous terrain and geography. However, sediment laden water is responsible for the erosion in the bucket. This research uses the reference design of the Pelton turbine from one of the hydropower in Nepal and aims to analyse the bucket surface to reduce the rate of erosion by enhancing the mid-section of the bucket profile through the application of Bezier curves, along with parametric modeling of the bucket's depth. Bezier curves were generated by using 4 control points to define the bucket’s profile which allows for smooth and precise shaping. Three different models of Pelton bucket were designed; each with increment of 4 mm depth and they were named as Bezier1, Bezier2 and Bezier3. Numerical study on the stationary bucket was performed using Computational Fluid Dynamics (CFD), implementing Tabak-off erosion model to study the Sediment Erosion Rate Density (SERD) on all Bezier curve-based buckets and were compared. Each model was simulated with particle sizes of 50, 100, 150 and 200 microns. The results showed that at 50 microns, the existing bucket has the lowest SERD with a value of 0.703 e −7 kg/m 2 /s. For particle sizes of 100, 150, and 200 microns, the Bezier1 bucket performed better with SERD values of 1.011 e −7 kg/m 2 /s, 1.293 e −7 kg/m 2 /s, and 1.693 e −7 kg/m 2 /s respectively. Hence, Bezier1 bucket performed best overall as, it has comparatively less value of SERD.