The mixed flow turbine, also known as Francis turbine, flows into the runner in a radial direction from all around, and then flows out of the runner in an approximate axial direction. The runner is composed of the upper crown, lower ring and blade. It is suitable for the range of water head from 20 meters to 700 meters, with simple structure, stable operation and high efficiency, but it is generally used in the range of medium water head. It is the most widely used type of hydropower station.