Kaplan turbine (English: Kaplan turbine) is a paddle-type water turbine, which has variable shape blades. It was developed by Austrian professor Victor Kaplan in 1913. He combined self-adjusting propeller blades and self-adjusting guide vanes to achieve high productivity benefits at large drop flows and large head height differences.
Kaplan turbines were first evolved from Francis turbines. Its invention can be used to generate electricity efficiently in hydropower plants with extremely low head heights, but extremely low head heights cannot be achieved with Francis turbines. Its designed head height range is 10-70 meters and the output can be from 5 to 200 MW. The diameter of the moving wheel is between 2 and 11 meters. The speed range is from 79 to 429 pm. The Kaplan turbine and its matched generators have a theoretical head height of 34.65 meters for the highest power generation efficiency. They are ten Kaplan turbines with a diameter of 4.8 meters in the Tacoma power plant in Venezuela in 2013. The power generation is 235MW.
Kaplan turbines are now widely used in high-flow, low-head hydropower plants.
Kaplan turbines are a type of internal-flow counterattack turbines, which means that after the working fluid flows into the turbine, the fluid pressure is changed and energy is lost. Energy is obtained from both the head and the kinetic energy of the current. This turbine design combines the functions of radial and axial turbines.