The Kaplan turbine is a propeller-type water turbine which has adjustable blades. It was developed in 1913 by Austrian professor Viktor Kaplan, who combined automatically adjusted propeller blades with automatically adjusted wicket gates to achieve efficiency over a wide range of flow and

water level Water level, also known as gauge height or stage, is the elevation of the free surface of a sea, stream, lake or reservoir relative to a specified vertical datum. Over long distances, neglecting external forcings (such as wind), water level ten ...

. The Kaplan turbine was an evolution of the

Francis turbine The Francis turbine is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today, and can achieve over 95% efficiency. The pro ...

. Its invention allowed efficient power production in low-

head A head is the part of an organism which usually includes the ears, brain, forehead, cheeks, chin, eyes, nose, and mouth, each of which aid in various sensory functions such as sight, hearing, smell, and taste. Some very simple ani ...

applications which was not possible with Francis turbines. The head ranges from and the output ranges from 5 to 200 MW. Runner diameters are between . Turbines rotate at a constant rate, which varies from facility to facility. That rate ranges from as low as 54.5 rpm ( Albeni Falls Dam) to 450 rpm. Kaplan turbines are now widely used throughout the world in high-flow, low-head power production. Kaplan turbine in Plave

Development

Viktor Kaplan, living in

Brno Brno ( , ; ) is a Statutory city (Czech Republic), city in the South Moravian Region of the Czech Republic. Located at the confluence of the Svitava (river), Svitava and Svratka (river), Svratka rivers, Brno has about 403,000 inhabitants, making ...

Austria-Hungary Austria-Hungary, also referred to as the Austro-Hungarian Empire, the Dual Monarchy or the Habsburg Monarchy, was a multi-national constitutional monarchy in Central Europe#Before World War I, Central Europe between 1867 and 1918. A military ...

(now in the

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), obtained his first patent for an adjustable blade propeller turbine in 1912. But the development of a commercially successful machine would take another decade. Kaplan struggled with

cavitation Cavitation in fluid mechanics and engineering normally is the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapor pressure, leading to the formation of small vapor-filled cavities in the liquid. When sub ...

problems, and in 1922 abandoned his research for health reasons. In 1919, Kaplan installed a demonstration unit in Poděbrady (now in the Czech Republic). In 1922, Voith introduced an 1100 HP (about 800 kW) Kaplan turbine for use mainly on rivers. In 1924 an 8 MW unit went on line at Lilla Edet, Sweden. This launched the commercial success and widespread acceptance of Kaplan turbines.

Theory of operation

The Kaplan turbine is an inward flow

reaction Reaction may refer to a process or to a response to an action, event, or exposure. Physics and chemistry *Chemical reaction *Nuclear reaction *Reaction (physics), as defined by Newton's third law * Chain reaction (disambiguation) Biology and ...

turbine, which means that the working fluid changes pressure as it moves through the turbine and gives up its energy. Power is recovered from both the hydrostatic head and from the kinetic energy of the flowing water. The design combines features of radial and axial turbines. The inlet is a scroll-shaped tube that wraps around the turbine's wicket gate. Water is directed tangentially through the wicket gate and spirals on to a propeller shaped runner, causing it to spin. The outlet is a specially shaped draft tube that helps decelerate the water and recover

kinetic energy In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion. In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Rober ...

. The turbine does not need to be at the lowest point of water flow as long as the draft tube remains full of water. A higher turbine location, however, increases the suction that is imparted on the turbine blades by the draft tube. The resulting pressure drop may lead to

. Variable geometry of the wicket gate and turbine blades allow efficient operation for a range of flow conditions. Kaplan turbine efficiencies are typically over 90%, but may be lower in very low head applications. Current areas of research include

computational fluid dynamics Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid dynamics, fluid flows. Computers are used to perform the calculations required ...

(CFD) driven efficiency improvements and new designs that raise survival rates of fish passing through. Because the propeller blades are rotated on high-pressure hydraulic oil bearings, a critical element of Kaplan design is to maintain a positive seal to prevent emission of oil into the waterway. Discharge of oil into rivers is not desirable because of the waste of resources and resulting ecological damage.

Applications

Kaplan turbines are widely used throughout the world for electrical power production. They cover the lowest head hydro sites and are especially suited for high flow conditions. Inexpensive micro turbines on the Kaplan turbine model are manufactured for individual power production designed for 3 m of head which can work with as little as 0.3 m of head at a highly reduced performance provided sufficient water flow. Large Kaplan turbines are individually designed for each site to operate at the highest possible efficiency, typically over 90%. They are very expensive to design, manufacture and install, but operate for decades. They have recently found a new application in offshore wave energy generation, see Wave Dragon.

Variations

The Kaplan turbine is the most widely used of the propeller-type turbines, but several other variations exist: * ''Propeller turbines'' have non-adjustable propeller vanes. They are used where the range of flow / power is not large. Commercial products exist for producing several hundred

watt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

s from only a few feet of

. Larger propeller turbines produce more than 100 MW. At the La Grande-1 generating station in northern Quebec, 12 propeller turbines generate 1368 MW. * ''Bulb'' or ''tubular turbines'' are designed into the water delivery tube. A large bulb is centered in the water pipe which holds the generator, wicket gate and runner. Tubular turbines are a fully axial design, whereas Kaplan turbines have a radial wicket gate. * ''Pit turbines'' are bulb turbines with a gear box. This allows for a smaller generator and bulb. * ''Straflo turbines'' are axial turbines with the generator outside of the water channel, connected to the periphery of the runner. * ''S-turbines'' eliminate the need for a bulb housing by placing the generator outside of the water channel. This is accomplished with a jog in the water channel and a shaft connecting the runner and generator. * The ''VLH turbine'' is an open flow, very low head "kaplan" turbine slanted at an angle to the water flow. It has a large diameter >3.55 m, is low speed using a directly connected shaft mounted permanent magnet alternator with electronic power regulation and is very fish friendly (<5% mortality). *The ''DIVE-Turbine'' is a vertical propeller turbine with double regulation by wicket gates and speed variation. It covers a range of application up to 4 MW with efficiencies comparable to standard Kaplan-Turbines. Due to the propeller design with fixed blades it is considered a fish friendly turbine.DIVE-Turbine
/ref> *'' Tyson turbines'' are a fixed propeller turbine designed to be immersed in a fast flowing river, either permanently anchored in the river bed, or attached to a boat or barge. File:Kraftwerk Ybbs-Persenbeug 7829 retusche.jpg, Model of a bulb or tubular turbine File:Kaplan-Rohrturbine modell-1 retusche.jpg, Model of a S-turbine File:StrafloSketch.svg, Schematic of a straflo-turbine File:Turbines VLH de la centrale du Rondeau à Échirolles.jpg, VLH turbines File:DIVE-TurbineSketch.svg, Schematic of a DIVE-Turbine

References

https://www.wws-wasserkraft.at/en

External links

National Historic Mechanical Engineering Landmark Kaplan Turbine
retrieved 2010 June 24
Bently Nevada Application Note on Hydro turbine vibration
retrieved 2014 August 14
3D model Kaplan turbine
retrieved 2021 February 10 {{Hydropower Water turbines Austrian inventions 20th-century inventions