Water turbine like a true turbine. Fausto Veranzio in his book "Machinae Novae" (1595) described a vertical axis mill with a rotor similar to that of a Francis turbine. Johann Segner developed a reactive water turbine (Segner wheel) in the mid-18th century in Kingdom of Hungary. It had a horizontal axis and was a precursor to modern water turbines. It is a very simple machine that is still produced today for use in small hydro sites. Segner worked with Euler on some of the early mathematical theories of turbine design. In the 18th century, a Dr. Robert Barker invented a similar reaction
Water turbine reaction turbines. Most water turbines in use are reaction turbines and are used in low (<) and medium () head applications. In reaction turbine pressure drop occurs in both fixed and moving blades. It is largely used in dam and large power plants Impulse turbines change the velocity of a water jet. The jet pushes on the turbine's curved blades which changes the direction of the flow. The resulting change in momentum (impulse) causes a force on the turbine blades. Since the turbine is spinning, the force acts through a distance (work) and the diverted water flow is left with