The Francis turbine is a grouping of a reaction turbine and an impulse turbine that uses the reaction force and impulse force of the water flowing through the rotating blades that generates electricity more efficiently. These turbines use to generate in different hydropower plants for producing electricity. These mainly work on two turbine flow theory. This article describes the operating principles, key components, and applications of the Francis turbine.
The reason for the high effectiveness of Francis turbines is their blades’ design. These blades revolve by using the impulse and reaction force of the water moving in the blades. This type of turbine uses both potential and kinetic energy to generate electricity, eliminating the main head availability problem. Therefore, it is also called a Mixed Flow turbine.
Working Principle of Francis Turbine
The blades of the Francis turbine design in such a way that one part of the blade structure produces a pressure differential between the blade’s opposite sides as the water flows through the blade. In contrast, the remainder part of the blade structure is combined using the impulse force of the water hitting the blades. The pressure difference and the impulse force generate sufficient energy to run the turbine at the desired speed. Therefore, the water potential energy and kinetic energy at the outlet reduce while the water’s inlet section energy increases.
Francis turbine has an ingenious design that uses both impulse and reaction forces to produce power. The power produced by this turbine is better than power produced by a single reaction turbine or impulse turbine under the same load conditions.