Francisturbinen

Francisturbinen are a type of water turbine widely used in hydroelectric power generation. Invented by American engineer James B. Francis in 1848, they are classified as reaction turbines, meaning they operate using both the pressure and kinetic energy of the water. Francisturbinen are characterized by their ability to handle a wide range of water heads and flow rates, making them exceptionally versatile.

The main components of a Francisturbine include the spiral casing, the stay vanes, the guide vanes, the runner, and the draft tube. Water enters the spiral casing which distributes it evenly around the stay vanes. The stay vanes are fixed and direct the water towards the adjustable guide vanes. These guide vanes control the flow rate and the angle at which the water strikes the runner. The runner, the heart of the turbine, has a series of curved blades that spin as water passes through them, converting the water's energy into rotational mechanical energy. Finally, the draft tube, a diverging pipe, efficiently discharges the water from the turbine while recovering some of the remaining pressure energy.

Francisturbinen are suitable for medium heads, typically ranging from 10 to 600 meters, and medium flow rates. Their efficiency is generally very high, often exceeding 90%. Due to their adaptability and efficiency, Francisturbinen are the most common type of turbine used in hydroelectric power plants globally, from small installations to large-scale dams. Their design has been refined over the years, leading to continuous improvements in performance and reliability.