Francis Turbine - Francis turbines lead in medium-head hydropower plants due to their versatility, durability, and efficient energy conversion.

The Francis Turbine is the most widely used type of reaction turbine in the world, renowned for its versatility across a broad range of operating conditions. Developed by James B. Francis in the mid-19th century, its design uses a runner with fixed blades that directs water inward along a spiral casing (scroll case) and then out axially.

The water enters under pressure and drives the runner through both impulse and reaction forces. The Francis turbine is the workhorse of the hydropower industry, best suited for medium-head and medium-to-high flow sites, which covers the majority of conventional dam-based hydroelectric projects globally. Its robust and compact design, high efficiency, and wide operating range make it the default choice for plants ranging from a few megawatts to well over a thousand. Modern Francis turbines are also heavily used in pumped storage applications as reversible pump-turbines, further solidifying their market dominance and technological importance.

Francis Turbine FAQs
What range of hydroelectric sites is best suited for a Francis turbine? The Francis turbine is best suited for medium-head and medium-to-high flow sites, which encompass the vast majority of traditional large and medium-sized dam installations worldwide.

Why is the Francis turbine considered the most common type globally? It is the most common because of its high efficiency and wide operational range, allowing it to be effectively applied to a greater variety of head and flow conditions than other turbine types.

In a Francis turbine, how is the water flow to the runner regulated? The water flow rate and the angle at which it hits the runner are precisely regulated by a set of adjustable wicket gates located just outside the runner periphery.