Investigation of reduction of Banki turbine shaft diameter to increase power.

The crossflow type turbine is a Banki turbine, which is usually used as a micro hydropower plant. The flow passage that enters through the nozzle usually hits the runner shaft so that the power received by the second stage of the blade was not optimal. This study aims to increase the turbine's power by reducing the diameter of the runner shaft using the drag formulation approach in aerodynamic theory. The 2D design drawings were created using AutoCAD, while 3D models used SolidWorks software. The power output in the first and second stages used a drag force in the CFD simulation. The water discharge was 0.0333 m3/s with a 5.5 m head. The simulated variation of the runner shaft diameter was 32 mm, 30 mm. 28 mm, 26 mm, 25 mm. 24 mm, 23 mm dan 22 mm. The original diameter was 32 mm with a total power of 1656 W. The simulation results showed that the most massive increase was a diameter of 26 mm with a total power of 1699.60 W. Reducing the shaft from 32 mm to 26 mm could increase the power by 2.56%. [ABSTRACT FROM AUTHOR]