CFD Analysis of the Most Favorable Gap Between the Main Runner and Booster Runner of Gravitational Water Vortex Turbine

The Gravitational Water Vortex Power Plant (GWVPP) is a power generation system designed for ultralow head and low flow water streams. Energy supply to rural areas using off-grid models is simple in design and structure and sustainable to promote electricity access through renewable energy sources in the villages of Nepal. The objective of this study is to determine the most favorable gap between the booster and main runners of a Gravitational Water Vortex Turbine (GWVT) to ensure maximum power output of the GWVPP. CFD analysis was used to evaluate the 30 mm gap between the main and booster runners, which was the most favorable gap for enhancing the plant’s power. In this study, the optimum power and economic analysis of the entire plant was conducted in the case of mass flow rates of 4 kg/s, 6 kg/s, and 8 kg/s. The system was modeled in SolidWorks V2016 and its Computational Fluid Dynamic (CFD) analysis was performed utilizing ANSYS R2 2020 with varying multiple gaps between the main and booster runners to determine the most favorable gap of the plant’s runner. This research concluded that optimum power could be achieved if the distance of the main runner’s bottom position be fixed at 16.72 %, i.e., the distance between the top position of the conical basin and the top position of the booster runner. At a mass flow rate of 8 kg/s, the plant generated maximum electric energy (3,998,719.6 kWh) comparatively and economically contributed 268,870.10 USD on an annual basis.