What is the Kaplan Turbine?

The Kaplan turbine is a water turbine that utilizes a propeller with automatically adjusting blades and gates. Kaplan turbines are ideal for low head, or situations of low water pressure dynamics, and are often situated in places where such a turbine is necessary given river flow conditions. Kaplan turbines allow for greater hydroelectric power production than was possible with previous designs restricted by propeller size and water flow.

A water turbine is a kind of rotary engine that produces energy gathered from water currents, typically rivers. Kaplan turbines, as did other turbine types, saw development during the Industrial Revolution for purposes of localized power generation in manufacturing. Victor Kaplan, an Austrian engineering professor, conceived the Kaplan turbine in 1913 but, because of initial problems with design, would not realize any widespread manufacture until years later.

The Kaplan turbine improved on a previously popular turbine type by using a differential self-adjustable propeller. It also features the use of adjustable gates to direct and control water pressure, with a chamber containing the propeller itself. This turbine type is one of the most widely used propeller turbine types in instances of high-flow water current and low-head power production.

Kaplan turbine design uses an inward flowing tube that serves as a compression chamber with a series of adjustable gates. As water is introduced through an inflowing gate, fluid becomes increasingly pressurized as it moves through the turbine and gives up its energy. Inflowing water is oriented at an angle within the tube encompassing the propeller and its shaft, causing the propeller to spin.

To recover potential energy loss, the Kaplan turbine features an exiting gate that slows water flow as it leaves the chamber. The adjustable blades and gates allow the turbine to operate continually through different water flow conditions. These features help to avoid losses in chamber pressure that would result in cavitations, or shock waves, that occur in enclosed propellers under low-pressure fluid conditions.

Kaplan turbines are expensive to manufacture. This is typically because of the materials involved and the large size of the units themselves. Despite this, the turbine’s efficiency, power output and ability to operate continually for several decades makes it a popular design in hydroelectric applications.

Its use of natural water current and its efficient method of power production mean Kaplan turbines provide a source of clean, renewable energy. Despite their clean energy production, Kaplan turbine shafts operate using lubricating fluids such as hydraulic oil. Special attention to maintaining seals and preventing loss of the fluid ensures that the oil does not contaminate a given locality’s waterway.