Parametric study of single-stage gravitational water vortex turbine with cylindrical basin

Gravitational water vortex turbine (GWVT) is one of the emerging micro-hydro power plants because it requires less expertise, low head and reduced setup space for installation. A detailed performance evaluation of the GWVT based on turbine performance curves is yet to be explored. With the help of mathematical expressions along with the experimentation, the present study presents different performance parameters (PPs) such as; rotational speed, torque, brake power and mechanical efficiency of single-stage GWVT under various flow and design conditions. The effect of vortex height, runner position, percentage submergence of blades, notch angle, blades aspect ratio, blades curvature, blades inclination, hub diameter, straight and conical edged blades on the PPs has been investigated. The analytical and experimental results are in a good agreement both qualitatively and quantitatively. The experimental results show that the vortex height and a good vortex shape with fully developed air core are the major parameters in deciding the performance of GWVT. Better performance of GWVT can be achieved at middle of the rotational speed range i.e. between the minimum and maximum load conditions with minimum possible notch angle and hub diameter, using inclined blades of zero curvature fixed near the bottom of the basin.