Improved Hydrodynamic Efficiency of Kaplan Hydro Turbine through Varying Blade Number and Length

Abstract

Kaplan hydro turbines are adjustable propeller blade turbines that are used in conventional hydroelectric power systems for the generation of electric power. Their mechanical efficiency based on their flexible and wide operating range of flow rates and head depends much on the runner blades and the alignments of the wicket gates. However, design modification of the geometry of the runner blade can be made for the improvement of mechanical efficiency. Computational Fluid dynamics simulation was employed to investigate the improved features of two hypothetical model turbine blades. SolidWorks® software was used for modeling the two categories of the turbine, named model A and model B Kaplan turbines. Model A has a short blade length of 130 mm twisted at an angle of 300, and its blade was varied from 2 to 6 blades. Model B has a longer blade length of 150 mm twisted at an angle of 300, and its blade was varied from 2 to 6 blades. The governing equations, which include continuity and momentum, were discretized using the Finite Volume method. The result shows that an increase in blade total surface area, as a result of an increase in blade length or blade number, increases the power output of the Kaplan hydro turbine.