Talk:Water turbine

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This article was the subject of a Wiki Education Foundation-supported course assignment, between 24 August 2021 and 20 December 2021. Further details are available on the course page. Student editor(s): Misplacedkey. Peer reviewers: Rdery.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 12:45, 17 January 2022 (UTC)

Removal

I removed the Quasiturbine additions to this page. Any positive displacement pump or engine can be plumbed up to pressurized water, and the Quasiturbine is not notable for this application. Duk 06:19, 9 Dec 2004 (UTC)

Most positive displacement engine concepts are not quite suitable for hydraulic for 2 reasons : 1) they require the fluid to go through a valve or a check-valve ; 2) the flow has to go forward and then backward (a severe inertial flow restriction). The Quasiturbine accept quasi-continuous flow at intake and at exhaust without any valve or check-valve. Furthermore, the flow is tangential and quasi-unidirectionnal, which make it less sensitive to fluid inertia reversal of direction. In fact, the Quasiturbine can act as a dosimetor valve, where the flow is proportional to the rpm. For water hydo-electric dam, the Quasiturbine offer a high efficiency at variable power level (conventionnal turbine works efficiently only at near fix design power) and because the Quasiturbine is a reversible hydraulic engine, it could be use to pump the water back-up outside peak consumption period ?

Good points. However, I will continue to object to noting Quasiturbine as a water turbine until it is notably used as one; a commercially successful application that is comparable to the other types listed, for example. Duk 20:51, 21 Dec 2004 (UTC)

The first part of the response contains some good points. The second is pure speculation. This appears to be typical of the promoters of this (and similar) engine developments. Andrewa 19:47, 27 October 2005 (UTC)

Head

Some anon editor changed the ranges for the various types. I've just checked Hydro Electric Engineering Practice and figure 1.2 is more consistent with the 17:47, 13 July 2005 edition, so I've reverted it. Anyone revising, please cite sources! --Wtshymanski 14:05, 15 July 2005 (UTC)

Environmental Impact

The authors of this article are propagating the myth that hydropower must always kill fish. In a properly designed dam and intake system (for example, one that utilizes wedgewire screening over a coanda effect intake for down-swim protection and fish ladders for up-swim protection) there is absolutely no fish kill required to produce clean power. Using modern technology (which is admittedly quite expensive) a completely wildlife-friendly hydropower system can be built, and such systems require less cleaning which makes them cost-competitive on an ongoing basis with systems that produce slightly more power by being much more environmentally damaging.

Dams are not inherently bad for the environment - many ecosystems, such as that of the fall line of the USA East Coast - are adapted to heavy impoundment by beavers and are not suffering from too many dams but rather from improperly constructed man-made dams. Hydropower, similarly, is not inherently bad for the environment, but rather antique methods and poor planning are bad for the environment.

Specific Speed

" Specific speed is defined as the speed in revolutions per minute at which a turbine would run at the best efficiency...under a head of one foot, its dimensions being adjusted to produce one horsepower." - the definition from "Hydro Electric Engineering Practice, Vol.II,", 2nd Ed., J. Guthrie Brown, Editor, Blackie and Son Ltd. London, 1970. Not flow, power. --Wtshymanski 23:16, 19 January 2006 (UTC)

The two definitions are almost the same, differing only by the density of the fluid: (one unit volume) (through one unit head) per (unit time) x (density) = (power)

1. From Layman's (see reference in the article)

   Some manufacturers define the specific speed nq of a turbine as the speed of a unit of the series of such magnitude that it delivers unit discharge at unit head... is not a dimensionless parameter and therefore its value varies with the kind of units employed in its calculation. The dimensionless parameter is the specific speed Ns given by the equation:... P.165

2. from [1]

   Specific speed is defined as "the speed of an ideal pump geometrically similar to the actual pump, which when running at this speed will raise a unit of volume, in a unit of time through a unit of head".

I think we need to look at the units choose the definition that matches $n_{s}$ in the article --Duk 23:54, 19 January 2006 (UTC)

Impulse turbines are not the same thing with water turbines.

Tidal Turbines

I have a question about where the various forms of turbine which are under rapid development at the moment to capture tidal stream energy fit into the categorisation of water turbines presented in this article. They don't seem to be either reaction or impulse turbines so is there another category that should be added? If so, does it have a conventional name? Chris55 (talk) 19:07, 17 August 2008 (UTC)

Buoyancy turbine

http://picasaweb.google.ca/evexano/UntitledAlbum —Preceding unsigned comment added by 99.199.26.97 (talk) 00:18, 2 June 2009 (UTC)

Definition

How exactly differs a turbine from a bladed rotor (as used in windmills, ...). Is the difference that a rotor also has plating to direct water into the rotor (eg like a funnel). Depending on the answer here, the article definition is to be changed or the article needs renaming.

Don't rename the article. Read the literature. --Wtshymanski (talk) 13:34, 30 September 2009 (UTC)

I don't want to change the name, just make the article more coherent at turbine its says:

A turbine is a rotary generator that extracts energy from a fluid or air 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 impart rotational energy to the rotor. Early turbine examples are windmills and water wheels.

This makes it sounds as if there is no difference, which is wrong ? Anyhow, the article needs to become more clear on this subject —Preceding unsigned comment added by 81.245.90.148 (talk) 10:56, 9 October 2009 (UTC)

Found own composed definition:

A turbine is the whole of a rotor and stator (or a electrical generator without the blades). Turbines are thus only used in electrical generators.

I'm guessing this is correct; if so change the definition of this article and change the image to make it more clear

81.245.90.148 (talk) 11:05, 9 October 2009 (UTC)

Time Line

In § "Time Line" it states that the early Roman designs "were found at Chemtou ... dating to the late 3rd or early 4th century AD", but in the uploaded photo in this section it says C.114 AD:

"Vertical axle watermill at Chemtou, Tunisia c.114 AD. The date is taken from the inscription CIL VIII, 10117. While the inscription was not attached to this structure, it is reasonably sure that the two are related."

Not sure which is correct?

WhiteMonkey (talk) 11:38, 19 July 2010 (UTC)

Diagram

Please can someone correct the spelling of "wicket" on the diagram at the top of the article? I can't believe they really meant "wicked"!Clampower (talk) 14:35, 4 March 2012 (UTC)

Fixed—thanks for spotting this. This was a quick and dirty edit, so apologies to both of the original contributors! --Old Moonraker (talk) 15:40, 4 March 2012 (UTC)

Power section in water turbine page

The maths in this section appears to be wrong, Power output, given the inputs in the page should be in kilojoules and kilowatts. This is important because I have found many people on the net using this equation, which is leading to a lot of confusion. If density of water is given in kg per cubic metre then the output will be in Kilowatts and not watts as mentioned. For instance if head or height of water is 150m , density of water is 1 (i.e.,1000kg/cubic metre) and flow of water is 0.095 m^^3/sec (i.e., 95 litres/sec) and gravity is taken as 9.8m/s^^2. Then output will be 105.717 kW and not 105.717 Watts which would be ridiculous. Kindly advise if my point is pertinent and valid. If no objection is received I will edit the section to show the correct units, although ideally mass should be shown in Newtons to get an output in Watts or Joules. DDjames — Preceding unsigned comment added by DDjames (talk • contribs) 11:53, 17 June 2012 (UTC)

Use SI units for everything and everything is in SI units. It just works. Mass kg, length m, volume m³, gravity N/kg (same thing as m/s^2 but better expresses the concept), density kg/m³, volume flow rate m³/s, power W.

Stating that the density of water is 1 without a unit is meaningless. The calculation assumes 100% efficiency and so overstates the power output but not enormously so. Using the numbers given then the actual power, assuming 100% efficiency, is 139793W, 140kW. Malcolm Boura (talk) 14:08, 24 February 2017 (UTC)

Rotary engine

I agree that we probably shouldn't say it's a "rotary engine." While technically it does rotate and it is a type of engine, "rotary engine" has a meaning of its own that's different from a water turbine. I'm not too crazy about "rotary motor" either. Maybe "rotating machine"? Or "turbine driven by water", which is a bit vacuous but is what my dictionary says? Kendall-K1 (talk) 18:14, 25 March 2016 (UTC)

I don't like "rotating machine" because it doesn't distinguish turbines from pumps. "Turbine driven by water" is fine by me, and it links nicely to turbine and hydraulic power, but I know that some dislike it in a lead as too obvious a tautology. Rotary motor is correct, although the term is most commonly applied (for water-powered motors) to those with pistons used for distributed hydraulic networks. Motor is better than engine (even under current WP target articles) as the definition of engines as fuel consumers and motors as energy transformers works here. Rotary engine is just wrong, and still wrong no matter how many times you add it. Andy Dingley (talk) 19:29, 25 March 2016 (UTC)

Yes, I see your point, but the sentence does go on to say "...that converts kinetic and potential energy of water into mechanical work" thus distinguishing it from a pump. At Turbine we have "a rotary mechanical device" which seems a bit jargon-y, and at Turbomachinery "machines that transfer energy between a rotor and a fluid." I checked a few textbooks but none come right out and define "water turbine" in a clear way. I'm going to change it to "rotary machine" for now because "rotary engine" is no good, but let's see what else we can come up with. Kendall-K1 (talk) 19:56, 25 March 2016 (UTC)

Well now that I've done that I looked at Machine and I'm not very happy with that either. Kendall-K1 (talk) 20:00, 25 March 2016 (UTC)

Comparison with water wheel

Quote "All common water machines until the late 19th century (including water wheels) 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."

• I can't make any sense of the term "water pressure head".
• Stream wheels do not contain the water during energy transfer and undershot wheels arguably do not.
• Breast shots wheels are both reaction and impulse. Overshot and backshot wheels predominantly reaction. Undershot and stream wheels are predominantly impulse.

Other

• (turbulent) vortex turbine (Turbulent's micro hydropower plants) [2] Setenzatsu.2 (talk) 22:55, 21 April 2020 (UTC)