Editing Water turbine (section)

==History==
[[File:Turbinaszerelés.jpg|thumb|right|The construction of a [[Ganz Works|Ganz]] water Turbo Generator in Budapest in 1886]]

[[Water wheel]]s have been used for hundreds of years for industrial power.  Their main shortcoming is size, which limits the flow rate and [[head (hydraulic)|head]] that can be harnessed. The migration from water wheels to modern turbines took about one  hundred years. Development occurred during the [[Industrial Revolution]], using scientific principles and methods.  They also made extensive use of new materials and manufacturing methods developed at the time.

=== Swirl ===
The word [[turbine]] was introduced by the French engineer [[Claude Burdin]] in the early 19th century  and is derived from the Greek word "τύρβη" for "whirling" or a "[[vortex]]". The main difference between early water turbines and water wheels is a swirl component of the water which passes energy to a spinning rotor. This additional component of motion allowed the turbine to be smaller than a water wheel of the same power. They could process more water by spinning faster and could harness much greater heads. (Later, impulse turbines were developed which didn't use swirl.)

=== Timeline ===
[[File:Roman mill at Chemtou.jpg|thumb|upright|Roman turbine mill at [[Chemtou]], [[Tunisia]]. The tangential water inflow of the [[mill race]] made the submerged horizontal wheel in the shaft turn like a true turbine.<ref name="Roman helix-turbine mill"/>]]
[[File:Water turbine grandcoulee.jpg|thumb|A [[Francis turbine]] runner, rated at nearly one million [[horsepower|hp]] (750 MW), being installed at the [[Grand Coulee Dam]], United States.]]
[[File:HydroelectricTurbineRunner.png|thumb|right|A propeller-type runner rated 28,000 hp (21 MW)]]

The earliest known water turbines date to the [[Roman Empire]]. Two helix-turbine mill sites of almost identical design were found at [[Chemtou]] and [[Testour]], modern-day [[Tunisia]], dating to the late 3rd or early 4th century AD. The horizontal water wheel with angled blades was installed at the bottom of a water-filled, circular shaft. The water from the [[mill race]] entered the pit tangentially, creating a swirling water column which made the fully submerged wheel act like a true turbine.<ref name="Roman helix-turbine mill">{{harvnb|Wilson|1995|pp=507f.}}; {{harvnb|Wikander|2000|p=377}}; {{harvnb|Donners|Waelkens|Deckers|2002|p=13}}</ref>

[[Fausto Veranzio]] in his book ''Machinae Novae'' (1595) described a vertical axis mill with a rotor similar to that of a [[Francis turbine]].<ref>{{cite news | last1=Rossi |first1=C |last2=Russo |first2=F |last3=Russo |first3=F | title=Ancient Engineers' Inventions: Precursors of the Present | publisher=Springer | year=2009 | isbn=978-9048122523}}</ref>

[[Johann Andreas Segner|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 hydraulic turbine that became popular as a lecture-hall demonstration.<ref>Musson, Albert and Robinson, Eric.  ''[https://books.google.com/books?id=ihxDGRwwzP0C&pg=PA45 Science and Technology in the Industrial Revolution]'', p. 45 (Taylor & Francis, 1969).</ref> The only known surviving example of this type of engine used in power production, dating from 1851,  is found at [[Hacienda Buena Vista]] in [[Ponce, Puerto Rico]].<ref name="Robert Sackett 1994. Page 16">R. Sackett, p. 16.</ref>

In 1820, [[Jean-Victor Poncelet]] developed an inward-flow turbine.

In 1826, [[Benoît Fourneyron]] developed an outward-flow turbine. This was an efficient machine (~80%) that sent water through a runner with blades curved in one dimension. The stationary outlet also had curved guides.

In 1844, [[Uriah A. Boyden]] developed an outward flow turbine that improved on the performance of the Fourneyron turbine. Its runner shape was similar to that of a [[Francis turbine]].

In 1849, [[James B. Francis]] improved the inward flow reaction turbine to over 90% efficiency. He also conducted sophisticated tests and developed engineering methods for water turbine design.  The [[Francis turbine]], named for him, is the first modern water turbine.  It is still the most widely used water turbine in the world today. The Francis turbine is also called a radial flow turbine, since water flows from  the outer circumference towards the centre of runner.

Inward flow water turbines have a better mechanical arrangement and all modern reaction water turbines are of this design. As the water swirls inward, it accelerates, and transfers energy to the runner. Water pressure decreases to atmospheric, or in some cases subatmospheric, as the water passes through the turbine blades and loses energy.

In 1876, [[John B. McCormick]], building on Francis's designs, demonstrated the first modern mixed-flow turbine with the development of the Hercules turbine, initially manufactured by the [[Holyoke Machine Company]] and subsequently improved upon by engineers in Germany and the United States.<ref>{{cite magazine|magazine=The National Engineer|date=August 1915|url=https://books.google.com/books?id=UhdnCBuWRF4C&pg=PA442|page=442|title=Chronology of Power Plant Apparatus|location=Chicago|volume=XIX|issue=8}}</ref> The design effectively combined the inward flow principles of the Francis design with the downward discharge of the [[Jonval turbine]], with flow inward at the inlet, axial through the wheel's body, and slightly outward at the outlet. Initially performing optimally at 90% efficiency at lower speeds, this design would see many improvements in the subsequent decades in derivatives under names like "Victor", "Risdon", "Samson" and "New American," ushering in a new era of American turbine engineering.<ref>{{cite book|title=The American Mixed-Flow Turbine and {{as written|I|t's [sic]|reason=Internet Archive error the original material is correct}} Setting|publisher=American Society of Civil Engineers|url=https://archive.org/details/americanmixedflo00amer/page/1265/|pages=1265–1266|last1=Safford|last2=Hamilton|first1=Arthur T|first2=Edward Pierce|year=1922}}</ref><ref>{{cite book|last=Smith|first=Norman Alfred Fisher|title=Man and Water: A History of Hydrotechnology|publisher=Charles Scribner's Sons|location=New York|pages=180–181|year=1975|isbn=9780684145228 |url=https://archive.org/details/manwaterhistory00smit/page/180/mode/2up}}</ref>

Water turbines, particularly in the Americas, would largely become standardized with the establishment of the [[Holyoke Testing Flume]], described as the first modern hydraulic laboratory in the United States by [[Robert E. Horton]] and [[Clemens Herschel]], the latter of which would serve as its chief engineer for a time.<ref>{{cite book|title=Dexter Sulphit Pulp & Paper Company v. Jefferson Power Company, et al.|url=https://books.google.com/books?id=rJenRyCYxl0C&pg=PA619|publisher=State of New York, Court of Appeals|year=1919|pages=619|quote=As the result of testing of experimental models there has been a gradual and progressive development in the uniformity of water wheels and water wheel patterns since the Holyoke Testing Flume was opened which did not exist before that time so that the wheels at the present time are more uniform in the United States.}}</ref><ref>{{cite book|title=To Establish a National Hydraulic Laboratory|author=US Congress, Senate Committee on Commerce|url=https://books.google.com/books?id=3gPcq-OZ2xsC&pg=RA1-PA59|quote=I have called the Holyoke testing flume the first modern hydraulic laboratory. There were such before 1881, but they were of so modest or minute dimensions that they failed to produce results suited to, certainly, modern practice|page=59|publisher=Government Printing Office|location=Washington, D.C.|year=1922}}</ref> Initially created in 1872 by [[James B. Emerson]] from the testing flumes of [[Lowell, Massachusetts|Lowell]], after 1880 the [[Holyoke, Massachusetts]] hydraulic laboratory was standardized by Herschel, who used it to develop the [[Venturi meter]], the first accurate means of measuring large flows, to properly measure water power efficiency by different turbine models.<ref>{{cite book|title=The Origins of the Turbojet Revolution|last=Constant|first=Edward W.|url=https://archive.org/details/originsofturboje0000cons/page/48/mode/2up|year=1980|location=Baltimore, Md.|publisher=Johns Hopkins University Press|pages=48–49}}</ref><ref>{{cite book|title=The Venturi Meter|last=Herschel|first=Clemens|publisher=Builders Iron Foundry|location=Providence, R. I.|year=1887|url=http://storage.lib.uchicago.edu/pres/2015/pres2015-0705-03.pdf}}</ref><ref>{{cite journal|page=254|volume=136|issue=3433|date=August 17, 1935|journal=Nature|doi=10.1038/136254a0|title=Invention of the Venturi Meter|quote=[The article] reproduces a letter from Herschel to the late Dr. Unwin describing his invention of the Venturi Meter. The letter is dated June 5, 1888, and addressed from the hydraulic engineer's office of the Holyoke Water Power Co., Mass. In his letter, Herschel says he tested a one-inch Venturi Meter, under 210 ft. head: 'I am now satisfied that here is a new and pregnant principle to be applied to the art of gauging fluids, inclusive of fluids such as compressed air, illuminating or fuel gases, steam, etc. Further, that the shape of the meter should be trumpet-shaped in both directions; such a meter will measure volumes flowing in either direction, which in certain localities becomes a useful attribute...'|doi-access=free|bibcode=1935Natur.136Q.254.}}</ref> While skepticism of certain [[weir]] calculations were held by European hydrologists, the facility allowed for standard efficiency testing among major manufacturers through 1932, by which time more modern facilities and methods had proliferated.<ref>{{cite book|title=Transactions of the International Engineering Congress, 1915|year=1916|url=https://archive.org/details/gri_33125015157650/page/n565/mode/2up|pages=498–499|publisher=Neal Publishing Company|location=San Francisco, Calif.}}</ref><ref name="barrett">{{cite book|title=The History of the Holyoke Water Power Company; A Subsidiary of Northeast Utilities, 1859-1967|via=[[Holyoke Gas & Electric]]|last=Barrett|first=Robert E.|location=Holyoke, Mass.|url=https://www.hged.com/widgets/image-widgets/history-widget-folder/barrett-book.pdf|archive-url=https://web.archive.org/web/20191212215156/https://www.hged.com/widgets/image-widgets/history-widget-folder/barrett-book.pdf|url-status=dead|archive-date=2019-12-12}}</ref>{{rp|100}}

Around 1890, the modern [[fluid bearing]] was invented, now universally used to support heavy water turbine spindles.  As of 2002, fluid bearings appear to have a [[mean time between failures]] of more than 1300 years.

Around 1913, [[Viktor Kaplan]] created the [[Kaplan turbine]], a propeller-type machine. It was an evolution of the Francis turbine and revolutionized the ability to develop low-head hydro sites.

=== New concept ===
{{Main|Pelton wheel}}
[[File:Pelton wheel (patent).png|thumb|right|Figure from  [[Lester Allan Pelton|Pelton's]] original patent (October 1880)]]

All common water machines until the late 19th century (including [[water wheel]]s) were basically reaction machines; water ''pressure'' head acted on the machine and produced work.  A reaction turbine needs to fully contain the water during energy transfer.

In 1866, California millwright Samuel Knight invented a machine that took the impulse system to a new level.<ref>W. A. Doble, "The Tangential Water Wheel", ''Transactions of the American Institute of Mining Engineers'', Vol. XXIX, 1899.</ref><ref>W. F. Durrand, ''The Pelton Water Wheel'', Stanford University, Mechanical Engineering, 1939.</ref> Inspired by the high pressure jet systems used in hydraulic mining in the gold fields, Knight developed a bucketed wheel which captured the energy of a free jet, which had converted a high head (hundreds of vertical feet in a pipe or [[penstock]]) of water to kinetic energy. This is called an impulse or tangential turbine. The water's velocity, roughly twice the velocity of the bucket periphery, does a U-turn in the bucket and drops out of the runner at low velocity.

In 1879, [[Lester Allan Pelton|Lester Pelton]], experimenting with a Knight Wheel, developed a [[Pelton wheel]] (double bucket design), which exhausted the water to the side, eliminating some energy loss of the Knight wheel which exhausted some water back against the center of the wheel. In about 1895, William Doble improved on Pelton's half-cylindrical bucket form with an elliptical bucket that included  a cut in it to allow the jet a cleaner bucket entry. This is the modern form of the Pelton turbine which today achieves up to 92% efficiency. Pelton had been quite an effective promoter of his design and although Doble took over the Pelton company he did not change the name to Doble because it had brand name recognition.

[[Turgo turbine|Turgo]] and [[cross-flow turbine]]s were later impulse designs.