Investigation of the Runner Blade Arrangements on a 3-Blade Kaplan Turbine Against Turbine Power

Kaplan turbine is one of the power generators in the micro-hydropower (MHP) plant. The power and efficiency of the turbine are influence by the turbine runner construction, the number of blades, the blade’s thickness, the arrangement of the blades, etc. This research aims to find out the best design of the runner blade arrangement on a three-blade of the turbine with variations in the height of the inner blade profile of RB-1 = −5 mm, RB-2 = 0 mm, RB-3 =  +5 mm, and RB-4 =  +10 mm from the height through Y-axis of the outer blade profile against the power efficiency. The gross head was 5.25 m, water discharge 0.125 m³/s with theoretical power of 6.131 kW. The runner blade profile used airfoil NACA-2412, the first step was to optimize the thickness of the blade by calculation and validated by the FEM software, the second step the blade profile optimize by CFD flow simulation software in momentary stop and rotation conditions. From the simulation result, it was found that in a momentary stop condition, the best variant in generating power is RB-1 which is 5955.97 W and turbine efficiency is 97.14%, while in a rotation condition, it is also RB-1 with 5743.89 W power and turbine efficiency 93.68%.