Pico-hydro power plants have the potential of hydroelectric power generators that can be applied in frontier areas to help the Indonesian government achieve Net Zero Emissions in 2060. A breastshot waterwheel (BWW) is one type of waterwheel that works at pico-scale hydropower, which is favorable due to its simplicity, fish and garbage friendliness, and good efficiency. While several studies have been conducted regarding the effect of kinetic energy on this waterwheel efficiency, the most influencing driving force for an efficient BWW is still questionable. This study variates the BWW bucket bend angle and location to optimize its performance and main effective force using Computational Fluid Dynamics (CFD) numerical simulations. The study analyzes the best bucket bend angle for optimal efficiency in pico-scale breastshot water wheels using analytical and numerical methods. The bucket bend angle is tested at 120°, 135°, and 150° at the center of the bucket’s total length, where the positions are tested at 0.25, 0.5, and 0.75 of the total bucket length at 135°. The CFD numerical simulation is conducted on a quasi-2D domain with on-site measurement-based velocity inlet boundary conditions. Based on the analytical calculations, the maximum efficiency could be obtained at 49.21% at 0.314 rad/s of angular velocity. On the other hand, the CFD numerical simulations found that the highest efficiency is obtained at a bend angle of 150° in half of the bucket’s length. The highest efficiency is 47.33% @ 0.314 rad/s. The critical finding is that the filling ratio exceeds the maximum bucket-only filling ratio at optimum conditions, requiring the surrounding wall to hold the water. This finding indicates that the gravitational force is highly significant. The more profound analysis also found that the impulse force effect is small but needs to be addressed so that it does not harm the BWW performance.

Mr.

Nurhadid