The Effects of Blade Height on the Efficiency of Gravitational Water Vortex Turbine

This paper presents the results of a study on the effect of blade height on the efficiency of a free-vortex water turbine. Laboratory experimentation was conducted to find the shaft power generation and the efficiency of the turbine. Water turbines with six blades and four different heights (208 mm, 248 mm, 288 mm, and 320 mm) were built and tested to determine the most appropriate blade height. The turbines were tested in a conical basin with inlet and outlet diameters of 600 mm and 100 mm and a height of 800 mm, at volume flow rates of 0.0088 m³/s, 0.0105 m³/s, and 0.0108 m³/s. The results showed that the turbine with a blade height of 288 mm was the most appropriate, yielding the highest efficiency of 30,46% at a water flow rate of 0.0108 m³/s.