Kaplan turbine
Encyclopedia
Water turbine
A water turbine is a rotary engine that takes energy from moving water.Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy...
which has adjustable blades. It was developed in 1913 by the Austrian professor Viktor Kaplan
Viktor Kaplan
Viktor Kaplan was an Austrian engineer and the inventor of the Kaplan turbine.-Life:Kaplan was born in Mürzzuschlag, Austria into a railroad worker's family. He graduated from high school in Vienna in 1895, after which he attended the Technical University of Vienna, where he studied civil...
, who combined automatically adjusted propeller blades with automatically adjusted wicket gates to achieve efficiency over a wide range of flow and water level
Hydraulic head
Hydraulic head or piezometric head is a specific measurement of water pressure above a geodetic datum. It is usually measured as a water surface elevation, expressed in units of length, at the entrance of a piezometer...
.
The Kaplan turbine was an evolution of the Francis turbine
Francis turbine
The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....
. Its invention allowed efficient power production in low-head applications that was not possible with Francis turbines. The head ranges from 10-70 meters and the output from 5 to 120 MW. Runner diameters are between 2 and 8 meters. The range of the turbine is from 79 to 429 rpm.
Kaplan turbines are now widely used throughout the world in high-flow, low-head power production.
Development
Viktor Kaplan living in BrnoBrno
Brno by population and area is the second largest city in the Czech Republic, the largest Moravian city, and the historical capital city of the Margraviate of Moravia. Brno is the administrative centre of the South Moravian Region where it forms a separate district Brno-City District...
, Moravia
Moravia
Moravia is a historical region in Central Europe in the east of the Czech Republic, and one of the former Czech lands, together with Bohemia and Silesia. It takes its name from the Morava River which rises in the northwest of the region...
, now Czech Republic
Czech Republic
The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....
, 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
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...
problems, and in 1922 abandoned his research for health reasons.
In 1919 Kaplan installed a demonstration unit at Poděbrady
Podebrady
Poděbrady is a historical spa town in the Central Bohemian Region, Czech Republic. It lies on the river Labe 50 km east of Prague on the D11 highway. A historic milestone in the life of the town was the year 1905, when it was visited by the German estate owner Prince von Bülow...
, Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...
. In 1922 Voith
Voith
The Voith GmbH, which is headquartered in Germany, is a family-run corporation in the mechanical engineering sector with worldwide operations....
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
Lilla Edet
Lilla Edet is a locality and the seat of Lilla Edet Municipality in Västra Götaland County, Sweden. It had 4,936 inhabitants in 2005.The town Lilla Edet is situated on the eastern side of the Göta älv, a main river on the west coast of Sweden. It became known as a halt there...
, Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
. This marked the commercial success and widespread acceptance of Kaplan turbines.
Theory of operation
Reaction (physics)
The third of Newton's laws of motion of classical mechanics states that forces always occur in pairs. Every action is accompanied by a reaction of equal magnitude but opposite direction. This principle is commonly known in the Latin language as actio et reactio. The attribution of which of the two...
turbine, which means that the working fluid changes pressure as it moves through the turbine and gives up its energy. The design combines radial and axial features.
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
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
.
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 cavitation
Cavitation
Cavitation is the formation and then immediate implosion of cavities in a liquidi.e. small liquid-free zones that are the consequence of forces acting upon the liquid...
.
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 CFD
Computational fluid dynamics
Computational fluid dynamics, usually abbreviated as CFD, is a branch of fluid mechanics that uses numerical methods and algorithms to solve and analyze problems that involve fluid flows. Computers are used to perform the calculations required to simulate the interaction of liquids and gases with...
driven efficiency improvements and new designs that raise survival rates of fish passing through.
Because the propeller blades are rotated by high-pressure hydraulic oil, 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 permitted.
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 with as little as two feet of head.
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.
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 in where the range of head is not large. Commercial products exist for producing several hundred watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
s from only a few feet of head. Larger propeller turbines produce more than 100 MW. At the La Grande-1 generating station
La Grande-1 generating station
The La Grande-1 is a hydroelectric power station on the La Grande River that is part of Hydro-Québec's James Bay Project. The station can generate 1,436 MW and was commissioned in 1994–1995...
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.
VLH turbine an open flow, very low head "kaplan" turbine slanted at an angle to the water flow. It has a large diameter >3.55m, is low speed using a directly connected shaft mounted permanent magnet alternator with electronic power regulation and is very fish friendly (<5% mortality). VLH Turbine
Tyson turbine
Tyson turbine
The Tyson Turbine is a hydropower system that extracts power from the flow of water. This design doesn't need a casement, as it is inserted directly into flowing water. It consists of a propeller mounted below a raft, driving a power system, typically a generator, on top of the raft by belt or gear...
s 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.
See also
- Archimedes' screwArchimedes' screwThe Archimedes' screw, also called the Archimedean screw or screwpump, is a machine historically used for transferring water from a low-lying body of water into irrigation ditches...
- HydroelectricityHydroelectricityHydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
- HydropowerHydropowerHydropower, hydraulic power, hydrokinetic power or water power is power that is derived from the force or energy of falling water, which may be harnessed for useful purposes. Since ancient times, hydropower has been used for irrigation and the operation of various mechanical devices, such as...
- TurbineTurbineA turbine is a rotary engine that extracts energy from a fluid flow and converts it into useful work.The simplest turbines have one moving part, a rotor assembly, which is a shaft or drum with blades attached. Moving fluid acts on the blades, or the blades react to the flow, so that they move and...
- Water turbineWater turbineA water turbine is a rotary engine that takes energy from moving water.Water turbines were developed in the 19th century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy...
- Francis turbineFrancis turbineThe Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....
- Pelton turbinePelton wheelThe Pelton wheel is an impulse turbine which is among the most efficient types of water turbines. It was invented by Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse of moving water, as opposed to its weight like traditional overshot water wheel...
- Banki turbineBanki turbineA cross-flow turbine, Banki-Michell turbine, or Ossberger turbine is a water turbine developed by the Australian Anthony Michell, the Hungarian Donát Bánki and the German Fritz Ossberger. Michell obtained patents for his turbine design in 1903, and the manufacturing company Weymouth made it for...
or crossflow turbine - Gorlov helical turbineGorlov helical turbineThe Gorlov helical turbine is a water turbine evolved from the Darrieus turbine design by altering it to have helical blades/foils. It was patented in a series of patents from September 19, 1995 to July 3, 2001 and won 2001 ASME Thomas A. Edison . GHT was invented by Professor Alexander M...
, which axis is positioned perpendicular to the flow