Computational fluid dynamics of the free water flow through t-he water turbine adapted goose foot.

Indonesia has great water energy potential to be utilized as a future energy source, one of which comes from river water flow. The water turbine is an energy conversion machine that can transform the kinetic energy of the water flow into mechanical energy. One of the water turbines obtained from the value of Indonesian local wisdom is the goosefootwater turbine. To predict flow behaviour accurately and precisely, a tool that can be used to simulate the real phenomenon is needed, namely Computational Fluid Dynamics. The turbine is designed using Inventor 18 software which has a construction of 6 blades and 17 fins. The simulation was using Ansys (CFX) software in three stages; pre-processing, solving, and post-processing. In the pre-processing stage geometry is generated, determining and naming boundary conditions for meshing and setting up. Set up process in control solver uses k-epsilon and root mean square (RMS) residual criterion. The solving stage for running process uses local parallel and double precision settings. Post-processing stage, tangential speed and torque results are obtained. The fluid flow characteristics analysed are velocity and torque. The results of this study classify five flow behaviours with characteristics that can be distinguished based on the path traversed, namely free water flow (laminar, Re= 1869.11), fin hitting flow (transition, Re= 2872.79), flow between blades (vortex, Re= 8001.35), fin outflow (laminar, Re= 521.48; laminar, Re= 2000.05), and turbine outflow (turbulent, Re= 7192.91). The phenomenon of the water turbine blades moving forward causes the blade fins to close so that the compressive force of the water blocking the blades becomes smaller, and if the turbine blades move backwards the blade fins will open, so that thecompressive force on the blade fins becomes larger and can push the water turbine to rotate faster. This rotating impulsethat is getting faster and faster is what causes the goosefoot water turbine to extract water energy to the maximum. [ABSTRACT FROM AUTHOR]