The effects of blade number and turbine baffle plates on the efficiency of free-vortex water turbines

Abstract

This article presents the results of the study on the effect of blade number and turbine baffle plates on the efficiency of a free-vortex water turbine. The laboratory experimentation performed to determine the power generation efficiency. The 2 to 7 blade water turbines were built and tested to find the most appropriate number of blades, and the result showed the 5 blade turbine being appropriate because it yields the highest torque from receiving impact from water flow. Next, the baffle plates were designed and attached to the top and bottom of the turbine blades. Four different sizes of space from 25% to 100% of the curve area around the blades were used. Experiments were carried out at the water flow rates of 0.04 to 0.06m3/s. The finding showed the 50% proportion of the curve area being most appropriate, and the blades installed with top and bottom baffle plates had the highest efficiency of 43.83%, which was 6.59% higher than without baffle plates. It was also found that when the water flow rate increased, the system efficiency became higher.