The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency.
Francis inlet scroll at the Grand Coulee Dam
Side-view cutaway of a vertical Francis turbine. Here water enters horizontally in a spiral-shaped pipe (spiral case) wrapped around the outside of the turbine's rotating runner and exits vertically down through the center of the turbine.
Pawtucket Gatehouse in Lowell, Massachusetts; site of the first Francis turbine
Francis Runner, Grand Coulee Dam
A water turbine is a rotary machine that converts kinetic energy and potential energy of water into mechanical work.
The runner of the small water turbine
The construction of a Ganz water Turbo Generator in Budapest in 1886
Roman turbine mill at Chemtou, Tunisia. The tangential water inflow of the mill race made the submerged horizontal wheel in the shaft turn like a true turbine.
A Francis turbine runner, rated at nearly one million hp (750 MW), being installed at the Grand Coulee Dam, United States.