What is a Kaplan turbine

On August 7, 1913, the patent with the number 74244 was registered with the Imperial and Royal Patent Office at the time, which lays the foundation stone for the turbine by the engineer Viktor Kaplan, born in Mürzzuschlag, which is used around the world.

Kaplan's credit for the controllability of the impeller

The Kaplan turbine is an axial flow water turbine with adjustable blades. It is usually installed vertically so that the water flows through the Kaplan turbine from top to bottom. The three-phase generator is usually installed above the Kaplan turbine so that the kinetic energy generated by the impeller can be transmitted to the generator rotor via a vertical shaft without any deflection losses. The achievable efficiencies are in the range of 80-95%. The Kaplan turbine is characterized by the adjustable guide and impeller blades, as this enables the turbine to be regulated to the respective amount of water and height of fall and achieves higher levels of efficiency. The Kaplan turbine is predestined for use at low to very low heads as well as large and fluctuating flow rates, i.e. the Kaplan turbine is primarily used for hydroelectric power plants on rivers with large flow rates.

Kaplan - discoverer of cavitation in water turbines

The discovery of cavitation in ship propellers took place around the year 1890, when the drive was switched from steam engines to steam turbines. Only after several large Kaplan turbines had already been put into operation did you notice a very haunting operating noise from the turbine and at the same time the expected efficiency was not achieved. Around 1921 Viktor Kaplan and his assistant Slavik discovered cavitation in water turbines. The problem of cavitation was only manageable through constructive measures on the turbine and the success story of the Kaplan turbine and the respective further developments began.

Optimization potential for Kaplan turbines

Through decades of observations in practice, research and modern measurement technology (e.g. thermodynamic efficiency measurement, acoustic flow measurement, ...) as well as development tools (e.g. CFD / numerical simulation, ...), the efficiency of the Kaplan turbine has increased depending on the framework conditions of the power plant historical course increased significantly. In refurbish projects, depending on the age of the system, sensational additional services are achieved due to hydraulic and mechanical optimizations. There is increasing potential for improvement in the area of ​​the intake manifold and the transition between the impeller and the intake manifold.