Modeling, analysis and optimization of runner blade of Kaplan turbine

The Kaplan turbine is an inward flow reaction turbine, which means, working fluid changes pressure as it moves through turbine and change its energy. Power is recovered from kinetic energy of the flowing water. During this process stresses are built up among many parts of Kaplan turbine like guide vane, runner blade, screws, hub, shaft etc. However, wall thickness of hub is much bigger in size therefore stress analysis of hub is not necessary. The screws, pins etc. parts do not contribute much in weight & cost of turbine. Guide vanes are also show less stress parameters compared to runner blades. The runner blade design is the main factor for optimizing the Kaplan turbine design. Parameters which affect the runner blade optimization are material of blade, runner diameter, stress relive groove, thickness of blade. This paper investigates, static stresses, weight & cost of the blade and it was found that blade weight is reduced up to 500 Kg's and cost is reduced up to 4472 USD per blade.