Influence of Bucket Shape and Kinetic Energy on Breastshot Waterwheel Performance

Abstract

Nearly 10% of people in Indonesia do not have energy access because the energy sources are far away from where they live. Breastshot waterwheels represent a solution for this problem because they allow water energy potency up to 19 GW. To enable the use of waterwheels, this study develops a simple bucket shape that is easy to manufacture, considering its efficiency, and tests whether the kinetic energy contributes to the energy conversion process. There are three possible bucket shapes, namely straight, circular and thick. The computational fluid dynamic (CFD) method is a simulation approach used for determining the features of physical phenomena with six degrees of freedom (6 DoF). The study results show that the straight bucket has a better efficiency than other buckets do; the numerical results illustrate that this bucket has higher rotation and torsion than the others do. The straight bucket generates 120 W of power, with a potential energy of 318.8 W and efficiency of 37.6%. For the circular bucket, the power generated is 43.05 W, with an efficiency of 13.5%; this is better than the results for the thick bucket, which generates 19.3 W with an efficiency of 6%. Two-factor analysis of variance (ANOVA) without replication is used to determine the effect of the energy kinetic (inlet velocity) on the energy conversion process, and it shows no effect. Consequently, the breastshot waterwheel is classified as a reaction turbine. Thus, the straight bucket is recommended for use due to its higher generated power and easier manufacture compared with the other bucket shapes.