Water Turbine

A water turbine is a rotary machine that converts the kinetic and potential energy of moving water into mechanical work, a nineteenth-century development from the older water wheel that is now used chiefly to generate electricity at dams and other hydroelectric installations. The French engineer Benoit Fourneyron built an outward-flow turbine in 1826 that reached roughly 80 percent efficiency using blades curved in a single plane, and the American engineer James B. Francis improved the inward-flow reaction turbine in 1849, pushing efficiency above 90 percent and establishing testing methods that made the Francis turbine the most widely used water turbine in the world. The American inventor Lester Pelton created the Pelton wheel in 1879, an impulse turbine with a distinctive double-bucket design developed after he experimented with an existing paddle wheel called the Knight wheel, and later refinements of Pelton's design reached efficiencies of about 92 percent, making it the standard turbine for sites with a high head of falling water.