There are two types of axial flow turbine: fixed blade propeller turbine and Kaplan turbine. The blades of the fixed blade propeller turbine are fixed, but the structure is simple. When the water flow and output changes, the efficiency of it also changes and the average operation efficiency is lower, therefore fixed blade propeller turbine could be at the power station which the power is not big and the water flow does not change much, currently it is used for the hydraulic head range of 3-30 m. 
Francis turbine is one of the most widely used turbines. It has a compact structure, reliable operation and high efficiency, and can be used at different ranges of water flow. Large-sized Francis turbines are commonly used at hydraulic head range of 20-700m.