Preliminary Numerical Investigation on Varying Vortex Flow Field and Power Output of Gravitational Water Vortex Power Plant

Abstract: Gravitational Water Vortex Power System (GWVPS) is a low head, cost-effective method of extracting hydro power. However, it is considered a less efficient hydropower system; thus, more research is needed to improve its performance. In this paper, a numerical investigation was carried out to examine the performance of a gravitational vortex power system with a cylindrical basin and a 5-bladed curved vortex turbine attached. It was studied in terms of the velocity flow field and power output under varying vortex pool conditions. The Moving Reference Frame (MRF) in Ansys Fluent was used, along with the turbulent k-w SST in the Volume of Fluid (VOF) model. Four basins with varying basin outlet ratios of 0.17, 0.18, 0.20, and 0.30 were subjected to different rotational turbine speeds of 40, 60, 80, 100 and 120 revolutions/minute (RPM). The study showed that for an outlet ratio of 0.18 at 80 RPM, the water velocity was the maximum at the drain outlet but decreased thereafter for higher drain outlet ratios. The maximum power output for the cylindrical basin was 80 W indicating better performance. Keywords: Gravitational water vortex turbine, numerical method, hydro power output