Talk:Gas turbine

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Original source?[edit]

This page was mostly copied from www.encyclopedia.|Roadrunner]] 03:52, 8 Jun 2004 (UTC)

My appologies for my presumtion. I have restored what I took out. Pud 9:27, 7 Jun 2004 (PST)

Brayton Cycle[edit]

Thanks Wizzy for finding Brayton cycle. From my talk page, Wizzy suggests;

"please put all theory discussion on one page, take anything but overviews off the other pages, with prominent links on those pages to that page, so nobody is tempted to start all over again. Then all improvements happen in one place, as opposed to bad rehashes all over the place."

What do other people think? Where should Brayton cycle reside (it is only applicable to gas turbines), and should some of the theory on the Jet engine page be moved to Gas turbine? See Wizzy's comments at the end of Talk:Jet_engine

At the least, Brayton cycle needs a T-S and P-V diagram with graphical representations of shaft power and efficiency. I'll try to make these graphics.

Pud, 09:18, 8 Jun 2004 (PST)

Thanks User:Duk for a great graphic. I think there has been some great work done on this page. Wizzy 22:41, 9 Oct 2004 (UTC)

If I am not completely mistaken, the work output of the turbine is proportional to the area that is enclosed by the cycle diagrams. Consequently, the enclosed areas in both cycles diagrams should be of the same size. If this statement is correct, I think it will be nice to visualize this in the figure, e.g. by shading those areas and writing "W" or "Work out" into them.

Another issue: Does anyone know, whether the diagrams can also be used to derive a statement with respect to the efficiency of the turbine? Tomeasy (talk) 14:39, 6 December 2007 (UTC)

Quasiturbine[edit]

I removed the Quasiturbine edit, it has its own page, is a positive displacement engine and doesn't belong on this page. Duk 06:16, 9 Dec 2004 (UTC)

Capstone turbines[edit]

I've reverted a bunch of edits by 65.248.1.80 to this and various other turbine pages;

  1. foil bearing vs. air bearing, self explanitory, see relevent patents and literature... foil bearing is the correct term.
  2. Micro turbine vs. MicroTurbine®, anon editor keeps changing the term to the capstone tradmarked version. I keep changing it back to the non-trademarked version.
  3. 65.248.1.80 duplicated the micro turbine section as its own article and re-wrote it to sound like a sales brosure for capstone (example- capstone inveted micro turbines (not true)). I changed to re-direct back here.

This page still reads like an advert, can we have a diagram of a turbine which doesn't mention a company ? PeterGrecian

Yes, you may edit the captions to be more neutral (there is no requirement for these images that the companies be mentioned).--Duk 16:47, 25 Apr 2005 (UTC)

Confusing[edit]

From the Microturbines section:

Typical micro turbine efficiencies are 25 to 35 percent. When in a combined heat and power cogeneration system, efficiencies of greater than 80 percent are commonly achieved.

From the Turbines in Vehicles section:

Firstly, small turbines are fundamentally less fuel-efficient than small piston engines.

This is very confusing to a layperson reader. To my knowledge a car piston engine is only about 10% efficient. How come micro turbines are so efficient and small turbines are so inefficient?

A few lines explaining the reasons for this discrepancy would be very helpful. 137.222.40.132 15:00, 5 October 2005 (UTC)

I don’t know where the cogeneration efficiency number came from, it seems unreasonably high. I have never seen a heat rate better than the high 5000’s from any cogeneration process or low 6000’s for any combined cycle process, and these are usually larger gas turbines.
Gas turbines are less efficient in automotive uses because they do not operate as efficiently at lower load and do not respond well to quick changes in load. Considering how often an automobile changes the load of the motor, with demand constantly ranging from 10-100% of rated output, a gas or diesel is better suited to handle these changes in demand.
The Otto cycle, or IC gasoline/diesel, efficiency is based on the compression ratio that the cylinder operates at. The higher the compression, the higher the thermal efficiency, that’s why diesels which typical operate at 20:1 are more efficient (low 40%’s) than gasoline which operates at around 9:1 (low 30%’s). Total efficiency of Otto cycle applications is lower from things like flywheel losses, transmission losses, wind resistance, friction losses between the pavement and the tire, and a number of other mechanical, rather than cycle losses. This and the fact that gasoline and diesel engines, in automotive use, operate much closer to their optimal efficiency point than do gas turbines.
I hoped this clarified things a bit. TDC 17:49, 5 October 2005 (UTC)


Yes, thanks. Perhaps we should incorporate the above into the section "Gas turbines in vehicles" to explain the reasons of inefficiency to the reader. Also, what you say suggests that gas turbines can be efficient when used in a hybrid vehicle. Are they more or less efficient than otto cycles in this case, or about the same? Would be a useful fact to mention too.
In the text it says that turbine engines are fundamentally less fuel efficient than piston engines. Is that not true then? 82.45.37.106 12:30, 13 October 2005 (UTC)
i wonder why there is no mention of Tesla Turbines .. peekay


from the "gas turbines in vehicles" section: " Their power-to-weight advantage is far less important. Their use in hybrids reduces the second problem " What ???? -- 83.245.48.112

Yes, it is unclear. I believe it is referring to this problem, "However, they are not as responsive and efficient as small piston engines over the wide range of RPMs and powers needed in vehicle applications." If the turbines are used in hybrid vehicles, they can be operated at their most efficient power level, with any excess power charging the batteries. The batteries and electric motor are more responsive, too. They could also add to the power than the turbine can supply at times of peak demand. If the batteries are full and the turbine's power is not needed for propulsion at the moment, it could be shutoff until it is needed again. This is what I think that it is trying to say. It assumes that the turbine can be turned on and off relatively quickly and efficiently, like piston hybrid engines, which are relatively small, operate at their peak conditions (as described above) and can be turned on and off almost instantly. -- Kjkolb 23:31, 3 July 2006 (UTC)

External links to manufacturers[edit]

I removed the external links to turbine manufacturers. Their websites are not useful for someone who wants to know how turbines work. They are only useful for someone who wants to buy a turbine. The only information about gas turbines that they have is the features of their products. If the idea is to tell readers who the major manufacturers are, it can be done in the article without links. For example, it could say: GE, Solar Turbines, Siemens, Mitsubishi... are the largest manufacturers of gas turbines. The links were essentially an advertisement and people kept adding links to their company or a company from their part of the world. I also removed the link to the decentralized energy website, as that is not what the article is about and the website is focused on making a case for decentralized energy, not how the technology works. -- Kjkolb 22:13, 3 May 2006 (UTC)

I agree, unlinked company names are okay but corporate website links are not. KyuzoGator 14:37, 14 November 2006 (UTC)

removed images[edit]

I removed some images. The first two didn't have any useful information and the group as a whole was unformatted. --Duk 15:34, 2 December 2006 (UTC)

GTS Finnjet correction[edit]

In section 10.2 (commercial maritime gas turbines) the claim is made that GTS Finnjet was the the first large vessel to use gas turbines for main propulsion in 1977. In fact, before that date, there had been a number of experiments in which gas turbines were used on seagoing commercial vessels. The earliest of these experiments may have been the Shell tanker "Aurus" (Anglo Saxon Petroleum) - circa 1949.

Between 1970 and 1982 the container company "Seatrain" operated a scheduled container service across the North Atlantic with four 26000 tonne dwt. container ships. Those ships were fitted with twin Prat & Whitney gas turbines which were broadly similar to the type of engine subsequently fitted in GTS Finnjet. The four Seatrain container ships were named Euroliner, Eurofreighter, Asialiner and Asiafreighter. They were employed continuously on a regular container service between ports on the eastern seaboard of the United States and ports in north west Europe for a number of years before GTS Finnjet was built. However, like GTS Finnjet, they began to experience difficulty with rising fuel costs following the dramatic OPEC price increases of the mid-nineteeen seventies. The engine systems on the Seatrain ships were modified to permit the burning of a lower grade of fuel ( standard marine diesel ). These modifications were partially successful insofar as it was proved that this grade of fuel could be used in a marine gas turbine, but the savings made were less than anticipated due to increased maintenance requirements. After 1982 the ships were sold, then re-engined with more economical diesel engines. Because the new engines were much larger, there was a consequential loss of some cargo space. Jim Fowler —Preceding unsigned comment added by 81.145.241.60 (talk) 14:41, 5 October 2007 (UTC)

Please go aheas and edit the article correctly. The additions about Finnjet were made based on information I had at the time and did not know about the Transatlantic GTS freighters. The Finnjet would probably still deserve a mention as the first passenger-carrying gas turbine -powered ship (and of course the first ferry). -- Kjet 19:06, 5 October 2007 (UTC)
Golden Gate Ferry put into service the MS Marin, a gas turbine powered passenger ferry, six months before the GTS Finnjet. I can't find a reference for when it was laid down but would assume it was prior to the Finnjet. The page for the Finnjet does state that it was the first gas turbine powered car ferry; the MS Marin is a passenger-only ferry. Philip F. Spaulding, the naval architect for the MS Marin, has a reference[1] on his page to an article that state's the service date of the MS Marin. . --173.164.165.242 (talk) 18:13, 21 November 2014 (UTC)

References

Marine Gas Turbine Usage[edit]

Early CODOG naval vessel:

http://en.wikipedia.org/wiki/Peder_Skram_(F_352)

The Germans had CODAG frigates even earlier:

http://en.wikipedia.org/wiki/K%C3%B6ln_class_frigate

The 378 class wasn't the first Coast Guard Cutter with gas turbines. The A-Class 210, built a few years earlier, had Solar GTs in a CODAG setup, although this is not reflected on their wikipedia page: http://en.wikipedia.org/wiki/USCGC_Reliance_%28WMEC-615%29 And there was a 95(82?)ft patrol boat experimentally fitted with a GT back in the 1950's, although I have not yet been able to find a reference to this.

The Chevron Oregon deserves mention as the first purpose-built gas turbine tanker. This vessel used a turbine-electric plant, and due to the energy crisis of 1973 and disputes with the builder, was not a great success. I believe, but cannot find reference to, they were later converted to diesel power.

http://www.gbrx.com/gunderson/chapters8-12.pdf

Australia was also a pioneer in this area; the Seaway Prince RO/RO vessel built by the Whyalla Shipbuilding and Engineering Works has the distinction of being the first gas turbine-electric vessel to enter service. http://www.austehc.unimelb.edu.au/tia/516.html —Preceding unsigned comment added by 152.121.19.11 (talk) 18:02, 12 October 2007 (UTC)

On 1-Dec-2012 user 67.168.209.186 altered the Chevron Oregon paragraph above, adding new information. I have reverted the change of a prior user's comment, and reproduced the changed paragraph below for reference:
The Chevron Oregon deserves mention as the first purpose-built gas turbine tanker. This vessel used a turbine-electric plant, and due to the energy crisis of 1973 and disputes with the builder, was not a great success fuel-wise, but were nevertheless valued for their ability for quick turnaround. I believe, but cannot find reference to, they were later converted to diesel. (They were not converted. There were studies to convert the GT's to heavy oil, but that would have required conversion to simple cycle from regenerative cycle, thus the advantage of the cheaper fuel would be lost.)
Rwessel (talk) 07:06, 1 December 2012 (UTC)

Tank use information[edit]

I've moved the information of the use of gas turbines in tanks from that article to this one as part of a clean-up of tank. I hope that you agree that this a better home for it and accept this (sometimes poorly written / formatted) text in your excellent article. Dhatfield (talk) 15:41, 15 April 2008 (UTC)

History[edit]

The history section seems to be mostly about steam turbines, and doesn't mention many major historical events for gas turbines. What about the Armengaud-Lemale engine? What about Holzwarth and Stodola? Theory is missing almost entirely -- dissociation, diluted combustion, etc. DonPMitchell (talk) 17:01, 24 July 2008 (UTC)

See History_of_the_internal_combustion_engine. Wizzy 20:44, 1 August 2009 (UTC)
I am missing Thomas Edison in the list of inventors. He was the first who developed a working gas turbine. --84.141.38.204 (talk) 20:19, 1 August 2009 (UTC)

Intro[edit]

The intro has experienced some creep since this revision. Duplication, rambling, and I think the following phrase isn't quite right; The heated air with or without products of combustion is expanded in a turbine resulting in work output, a substantial part, about two-thirds, of which is used to drive the compressor.; what about the waste heat? --Duk 05:44, 2 September 2008 (UTC)

revised intro per above. --Duk 19:56, 18 September 2008 (UTC)

Gas turbine and combustion turbine[edit]

A gas turbine is different from a combustion turbine. A combustion turbine is a gas turbine that uses combustion. A compressed gas turbine is a gas turbine that uses compressed gas (i.e. compressed air).--147.84.132.44 (talk) 09:54, 7 September 2010 (UTC)

Correct, but unhelpful. "Gas turbine" has an accepted common use (so common I'm not even going to spell it out) and a "non-combustion turbine" is the minor form that warrants disambuiguation, if any. Go and write it if you like, it's a good topic for an article, but it doesn't belong under gas turbine, as that particular name. Andy Dingley (talk) 10:12, 7 September 2010 (UTC)
As an expansion of that, there's a thermodynamic reason why "gas turbine" has become synonymous with combustion turbines. I note that you've been adding See alsos to Compressed air engine. Yet compressed air alone is a very minor part of the gas turbine picture. They're used where their compactness and power density is useful, not because they're especially efficient as major power producers. The reason is that compressing air alone doesn't make for an effective turbine - there's not enough energy density in the working fluid. It works for water because liquids are denser. It works for steam turbines and combustion turbines because there's heat energy in the working fluid too (and this heat becomes useful work in the turbine). For a simple unheated compressed gas though, it's marginal and fundamentally limited to remaining so too. Andy Dingley (talk) 10:18, 7 September 2010 (UTC)

Gliders - Self Launched[edit]

Mini Turbines are finding new applications in self-launching gliders. Would like to see a picture and a little text to go with it. These mini turbines are stowed after takeoff and the glider then glides. —Preceding unsigned comment added by 63.133.206.2 (talk) 23:39, 1 December 2010 (UTC)

Buses[edit]

The most successful design by Designline is now operated in 5 cities in 6 countries, with over 30 buses in operation worldwide, and order for several hundred being delivered to Baltimore , and NYC.

I would love to hear which city is located in two countries. Apart from that, numbers below 10 should be written as words, and the space between 'Baltimore' and the comma is extraneous. SeverityOne (talk) 11:20, 14 December 2010 (UTC)

I only know of a city located on two continents (Istanbul), but a city in two countries would be a first. :-D -- 145.228.61.4 (talk) 13:12, 17 February 2011 (UTC)

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Basic theory issue with gas flow[edit]

I have an issue with the words in the second paragraph of the introduction where it says "The products of the combustion are forced into the turbine section." because of the use of "forced". The products of the combustion flow into the turbine section section because the arrangement of the combustion-ducts creates a lower pressure at the face of the turbine compared with that of the compressor outlet end. Using forced in this context is misleading. Lin (talk) 23:16, 15 September 2012 (UTC)


Main image[edit]

The main image showing the gas turbine variations is great but they need to be numerated so they can be properly referenced in the description.

Image author here. Can do! Should I also remove the top item (ie. the useless gas turbine alone)? That was a difficult decision to make when drawing the image. Ariadacapo (talk) 06:45, 18 May 2013 (UTC)
Yes, please remove the top engine - no power output does seem a waste in an otherwise excellent diagram. Also, could the turbo-shaft be shown to accommodate both electric power generation and connection to helicopter rotors, ship propellers and ground vehicle traction (e.g. tanks). Perhaps just the shaft going to the right with a rotation arrow around it and possibly with the shaft coming from a second turbine.  Stepho  talk  14:28, 18 May 2013 (UTC)
Done (removed principle item and numbered the rest). We cannot do everything in one drawing, however. I did not include a rotor or other accessories because it clutters the drawing very quickly. A sectioned shaft can also easily mislead (it’s hard to convey the fact that this extra shaft carries power and requires a turbine extension compared to the turbojet case). The same goes for multiple-spool / free turbine configurations. These can all be explored in separate diagrams but wanting to put too much in there will kill the purpose. If the article starts improving I will spend the time needed to make those extra diagrams. Ariadacapo (talk) 08:59, 21 May 2013 (UTC)
Ok, thanks.  Stepho  talk  09:52, 21 May 2013 (UTC)

CFD EL[edit]

Hi All, while researching the advancement in Gas Turbines, the article http://www.hcltech.com/sites/default/files/CFD_for_Aero_Engines.pdf provided great insights into Computational Fluid Dynamics for the analysis and design of components in aerospace industry. I have added the link as a reference. The articles is an unbiased take on the potential of the CFD tools and application of it to various aerospace problems.Vedanga Kumar (talk) 12:01, 22 December 2014 (UTC)

It doesn't say much though, does it? It paraphrases as "Lots of CFD is used to design gas turbines. It's a big-money market. We're not going to explain further." I can see this as a reference, should anyone challenge the claim "CFD is used". I couldn't see it as meeting WP:EL though, as there just isn't any depth to it. Andy Dingley (talk) 12:53, 22 December 2014 (UTC)

Amateur gas turbine section[edit]

This sentence struck me as odd/inaccurate: "In its most extreme form, amateurs have even rebuilt engines beyond professional repair and then used them to compete for the Land Speed Record." There's no citation for an example of amateurs having done that, but mostly I'm skeptical of the claim that something that is beyond professional repair has somehow not escaped the limits of amateur capability. Intrepidus (talk) 14:07, 11 February 2015 (UTC)

It's a well-known story, loads of sources for it. Art Arfons' J79 for Green Monster. A Starfighter ate a rock and the engine went for scrap. Rather than rebuilding the damaged blades, Arfons simply rearranged the ones left to balance it. Andy Dingley (talk) 14:37, 11 February 2015 (UTC)
Perhaps it is more accurate to say that the engine was beyond economic repair for its original application but an amateur rebuilt it anyway in modified form for a new application.  Stepho  talk  23:26, 11 February 2015 (UTC)

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Cleanup needed[edit]

Apparently editors are more interested in dragging people to dead talk pages than fixing articles, so here goes. The lead for this article is a mere paragraph (plus one sentence) long, as are most of the subsections. This is plainly not in line with the Manual of Style. Significant work is required to bring this article up to anywhere near GA-class; those tags help draw attention to this in the interim. I'll be re-adding them shortly, should I not find the time to do the work directly at present. I don't expect to be summarily reverted again. Chris Cunningham (user:thumperward) (talk) 17:04, 29 November 2016 (UTC)

So just what's wrong with the lead? (as you failed to note that in your tag-bombing) And the "complexity" tag is simple crap. Andy Dingley (talk) 17:11, 29 November 2016 (UTC)
I agree with Andy - the lead is a "concise overview of the article's topic" (from WP:LEAD). This lead describes the main points of a gas turbine in relatively simple language without getting bogged down in details. I see the current lead as not having any real problem and not requiring a tag. Of course, if you have something concrete in mind then you are free to edit the article - we might even agree with it.  Stepho  talk  22:07, 1 December 2016 (UTC)
There is nothing which so easily identifies editors as having a deficiency in ability to fully comprehend policy as literally skimming the first paragraph of WP:LEAD (a document which wouldn't fit into the RAM of my first home computer) and boldly declaring an understanding of it. Anyway, I suppose I'll fix this myself in due course. As for the complexity tag, it's proven impossible in the past to explain to certain editors the concept of writing for a general audience, but I suppose the mere evidence of it having been here and reverted serves a purpose for those who care about such things. Chris Cunningham (user:thumperward) (talk) 00:28, 15 December 2016 (UTC)
How about you drop the passive-aggressive whining at other editors and just answer the question: Just what's wrong with the lead? Andy Dingley (talk) 00:33, 15 December 2016 (UTC)
It isn't remotely fit for purpose. It should be an executive summary of everything notable in the article, rather than some sort of exercise in brevity which (as is endemic in technical articles) is practically worthless not only to a general audience but even to one which isn't already a subject-matter expert. But as you've requested dropping the passive-aggressiveness of not directly naming you, there is literally no point in explaining this to an editor whom I've been running around cleaning up after (and in the process significantly improving articles) for what must be around a decade or so now. This comment was for historical record than because I genuinely thought it'd have educational value. Chris Cunningham (user:thumperward) (talk) 00:41, 15 December 2016 (UTC)
The two methods for dealing with this are:
  • Drive-by tagging and hoping somebody else will deal with it.
  • Diving in and fixing it.
Feel free to rewrite it. If the community doesn't like it then at least it is a starting point for a discussion. Go for it!  Stepho  talk  01:57, 15 December 2016 (UTC)
Tagging helps me keep track of things I will do, in addition to flagging it for other editors. If I tag something, it should always be implied that I will eventually get round to it myself if nobody else does. FYI, people who perpetually attach the epithet "drive-by" to the tagging process are not likely to be paid much attention to on the subject. Tagging as a process isn't going anywhere. Get used to it. Chris Cunningham (user:thumperward) (talk) 08:40, 15 December 2016 (UTC)

───────────────────────── Drive-by tagging is where an editor puts a tag on a page and then never comes back. It takes 3 brain cells but relies on someone else to do the real work. Your edit added these tags but gave us no indication you planned to come back to do the work, making you look like a drive-by tagger. You have also been antagonistic in your discussion here. These facts make you look like an arsehole and people will treat you as such - get used to it.

Or we can work together. Make some changes and work with the community.  Stepho  talk  09:43, 15 December 2016 (UTC)

All of you should stay civil. "crap", "deficiency", "3 brain cells" aren't appropriate. Tagging seems less appropriate than adding a /*lead*/ section in the present talk page. This article is way from perfect but is near B-class and lacks only Referencing and citation. Everybody can agree to improve it.--Marc Lacoste (talk) 11:02, 15 December 2016 (UTC)
I second Marc Lacoste. None of the above interventions actually address the article content. Please stop. Ariadacapo (talk) 11:15, 15 December 2016 (UTC)
As I say, this discussion is more for the sake of historical record than because I expect any of the participants to actually be of any practical use in resolving the problem. I'll eventually end up fixing this myself. I'm proud of my record on that front. Chris Cunningham (user:thumperward) (talk) 01:03, 16 December 2016 (UTC)
I apologise if I came across as insulting. However, you can see that the existing editors don't see a problem and therefore, as you said, you will probably need to fix it yourself. For myself, the lead is a decent balance between engineering gobbledegook (unintelligible to most readers) and dumbed-down baby talk (useless). We aren't against you fixing it - we just don't know where to start.  Stepho  talk  01:24, 16 December 2016 (UTC)
I must agree with Chris Cunningham. Whenever anyone sees a problem, one should mark it by at least pointing it out. Tagging is evidently one Wikipedia way of doing so, and it is accepted by the standards. Further, one may not wish to do the corrections himself because of either a lack of understanding of the subject matter or because the original author may have special insight and be able to create a more cohesive and clear exposition on the subject matter. We are simply attempting to make the article better by pointing out shortfalls in clarity or composition, as well as nudging the author past what may just be a temporary writer's block. Every little bit helps, if given in a spirit of assuming the best.
It is sometimes difficult to see the problems of thought organization and information flow as it should be presented for the benefit of the lowest common denominator of reader. I often come to Wikipedia looking for information. If something is unclear, for whatever reason, it is my responsibility to point it out, as is every reader's. If something doesn't come up to standards there may be an issue with the requirements of the standards, or it may be just poor editing. Some leeway can be agreed to within the talk pages of a given article, and that is what we should be doing here. Marc Lacoste is correct in his comments, and while I believe there is need for cleanup, I also believe we can do it here, especially if the original author desires to apply his expertise. - KitchM (talk) 18:08, 22 January 2017 (UTC)

2005 Aviation week specs[edit]

http://www.togo84.com/spec05_gas_turbines.pdf --Marc Lacoste (talk) 09:49, 30 November 2016 (UTC)

Gas Is Similar To Steam Turbine?[edit]

"The basic operation of the gas turbine is similar to that of the steam power plant except that air is used instead of water." Okay, gas is mixed with air to create a combustion. But is gas mixed with water to create a combustion? That can't be right. - KitchM (talk) 00:42, 21 January 2017 (UTC)

A steam turbine is similar to the back part of a gas turbine. The steam turbine doesn't have a compressor, combustion chamber or afterburners.  Stepho  talk  00:51, 21 January 2017 (UTC)
So it sounds as though it isn't similar at all, right? Obviously there was no distinction between the "front" part and the "back" part, nor would one wish to confuse the reader that way. We should just remove that unnecessary sentence anyway since it serves no purpose. - KitchM (talk) 04:53, 22 January 2017 (UTC)
I second kitchM. --Marc Lacoste (talk) 06:55, 22 January 2017 (UTC)
  • There are two meanings to "gas turbine". One is as a turbine: the smaller part of the whole. The other is as the engine commonly used in aircraft: the compressor, the combustion chamber and the turbine. Any confusion stems from not clearly showing which of these two meanings is in effect at the time. Andy Dingley (talk) 12:23, 22 January 2017 (UTC)
  • Logically, the subject of this article would be "Gas turbine engine" but the abbreviation has become the WP:Common name, so we use it even though it creates the confusion seen above. Jim.henderson (talk) 13:22, 22 January 2017 (UTC)
Then that is an obvious mistake and needs immediate correction. - KitchM (talk) 16:56, 22 January 2017 (UTC)
Perhaps, but we really need a clear consensus here first, as this is a long-standing title. As such, I've reverted the move. - BilCat (talk) 23:15, 22 January 2017 (UTC)
A dumb, over-simplistic move is The Wikipedia Way though. 8-( Maybe we can find some hyphens and capitalisation to argue over too? Andy Dingley (talk) 23:50, 22 January 2017 (UTC)
I hate it when someone does that. There had been no discussion and the notice I got had no information about what was going on and/or why. Very confusing. Had to look all over to find out how that happened, and stumbled upon the explanation here. Thanks for fixing that, BilCat. Much appreciated. So maybe someone can tell me how we got from a simple bad grammar issue to one of a name change. What's going on. I'm confused. - KitchM (talk) 02:00, 24 January 2017 (UTC)
You started it by asking for a clarification vs steam turbine. Not a grammar issue but a meaning issue. So after seeing the discussion, user:MidAtlanticRidgeback went ahead and changed the article name to avoid confusion, but User:BilCat revert it stating there wasn't enough consensus for such a bold move on a long-standing title. So we have to build a consensus. I agree this isn't straightforward and the way WP works is convoluted :) --Marc Lacoste (talk) 08:49, 24 January 2017 (UTC)

I support the new name. --Marc Lacoste (talk) 06:01, 23 January 2017 (UTC)

What new name? - KitchM (talk) 02:00, 24 January 2017 (UTC)
"Gas turbine engine" --Marc Lacoste (talk) 08:27, 24 January 2017 (UTC) To clarify, I support a clarification vs steam turbine : the present article describes a complete engine with compressor+combustor+turbine, not only the turbine part which is indeed comparable with a steam turbine. --Marc Lacoste (talk) 08:52, 24 January 2017 (UTC)

───────────────────────── I'm sorry about anyone's confusion, but I never, ever thought the name should be changed. If someone thinks that is a good idea, then that should be made into a new section. (Gas Turbine is the correct name, IMHO.) So please allow me to start over.

To be more specific, there should be three paragraphs instead of two. Here is my suggestion:

A gas turbine, also called a combustion turbine, is a type of internal combustion engine, or ICE. It has an upstream rotating compressor coupled to a downstream rotating turbine, with a combustion chamber in between.

The basic operation of the gas turbine is similar to other ICE's. Fresh atmospheric air is pulled in by a compressor that brings it to higher pressure. Fuel is injected into the air and ignited in the combustion chamber area, whereby said combustion generates a high-temperature, expanding flow of hot gases. These hot gases push out thru the turbine, which in turn rotates a shaft to generate work output in the process. The energy that is not used for shaft work comes out in the exhaust gases, so these have either a high temperature or a high velocity, or both.

The turbine shaft work is used to drive the compressor and other devices such as an electric generator that may be coupled to the shaft. The purpose of the gas turbine determines the design so that the most desirable energy form is maximized. Gas turbines are used to power aircraft, trains, ships, electrical generators, and tanks.

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Marine turbines and DES Auris[edit]

(Moved from main article [1]) Andy Dingley (talk) 10:44, 18 September 2018 (UTC)

The DES Auris was my first ship and I joined in Hebburn whilst the Gas Turbine was being installed. One problem was that ,due to extremely high temperatures,the exhaust gases did not go via the funnel but via a separate exhaust fitted on top of the after accommodation,forward and to starboard of the funnel.This exhaust was prone to carbon build up,and,at least on three occasions,this build up caused a fire,with the result that flames some twenty feet high occurred. No damage was caused,but,on a white oil tanker,this was not welcome .

Additionally problems were experienced when attempting to manoeuvre with the gas turbine online.

On a later voyage,the trans Atlantic passage was attempted on the Gas Turbine alone. In cooler climates an initial speed of around eight knots was obtained,but,as external temperatures rose,so the speed reduced,and by the time the Caribbean was reached,we were down to three knots. — Preceding unsigned comment added by 82.16.200.255 (talkcontribs)

Andy Dingley (talk) 10:48, 18 September 2018 (UTC)
Thanks, I can find surprisngly little about the Auris.[1][2] Do you know anything about the gas turbine? Was it related to the naval turbines being developed, like the RM60 used on Grey Goose - and then rejected in favour of the re-purposed aircraft designs. Andy Dingley (talk) 10:51, 18 September 2018 (UTC)

References

  1. ^ "Auris". Tyne Built Ships.
  2. ^ Robert James Forbes; Denis R. O'Beirne (1957). The Technical Development of the Royal Dutch/Shell: 1890-1940.

Looking for explanation of 'Reverse-Flow Turbine'[edit]

Several articles about various gas turbine engines refer to some of them as 'reverse flow' types but I can't find any explanation of what is meant by this. At first I thought it might mean that a free turbine power shaft revolved in the opposite direction to the compressor but searches suggested it was combustors which were the reverse flow components - though I couldn't find any reference to this in the article on combustors either. The only article I've found on reverse-flow engines was about reverse-flow cylinder heads (for piston engines). I hope some nice knowledgeable person will agree this is an oversight! Thanks 86.150.255.84 (talk) 10:08, 12 February 2019 (UTC)

  • There are at least two well-known uses of "reverse-flow", although neither relate to the turbine disc.
Sectioned Welland, airflow from right to left
The first is the early Welland engine. This used reverse-flow combustors, as did several of the first engines. They're still used today, as single combustors, mounted at right angles to the axis, and for stationary gas turbines, such as APUs. A reverse flow combustor, because of countercurrent exchange like a reverse-flow heat exchanger, has a number of advantages for flame stability. Any instabilities give rise to a negative feedback effect because of the counterflow and so tend to damp out, whilst a through-flow combustor could start to oscillate destructively instead or simply flame-out. However there's also a thrust on the head of the combustor (either type), and it's useful for a jet engine to point that forwards!
The second is the Bristol Proteus turboprop. Our article is poor, so look at the 1949 Flight article instead. This engine was designed to be buried in a thick wing and fed by leading-edge inlet ducts to the rear of the engine, so it flows air from back to front (and back again, in a loop). Andy Dingley (talk) 11:05, 12 February 2019 (UTC)
Thank you, that's helpful for me at least. If anyone feels up to adding to existing articles then it looks to me as though the first thing to establish is whether the Proteus is unique - in which case the meaning in that particular case could best be explained within the Proteus article. There do seem to be enough different engines stated to have reverse flow combustors though for that to be a more general meaning which I think merits its own section somewhere..? 86.150.255.84 (talk) 22:44, 12 February 2019 (UTC)
  • The question of whether the Proteus was 'unique' or just 'weird' has always been a tricky one. It originated with the Bristol Theseus turboprop and as that used a heat exchanger it had an even more convoluted path. I don't know of any turbojets (or turbofans), i.e. jet engines reliant on thrust with a similar layout, other than the very early examples with reverse-flow combustors. There have been a few turboprops though (as these can trade off thrust for better internal efficiency) - the PT6 is a very common example (Annotated cross-section here). This uses both a reverse flow combustor (although annular, rather than multiple cans) and the whole engine (which is quite small) was usually mounted in reverse, so as to put the power turbine nearer to the propeller and avoid a long drive shaft passing through the main engine shaft. They're often mounted with a prominent exhaust elbow to turn the exhaust thrust to forward thrust. Any thrust from the combustor would also be forwards, although I suspect this is more by happy coincidence than deliberate. If you look at early (1950s) turboprops, these tended to combine both axial followed by centrifugal compressors and so had a diameter mismatch from the compressor exit to the turbine disc which often involved a convoluted path through the combustor.
Austin 250 bhp stationary turbine of the 1960s with a single elbow combustor
Going back to 1930s and 1950s gas turbines, these were large and designed for either power generation, ships or a few railway locomotives. They almost all used a single combustor and often of reverse flow, even a cyclone design or an L-elbow layout. Again, thrust wasn't a consideration. In the 1940s there was a war on and a focus on aircraft, by the 1960s this vast investment in the development of aircraft engines was making a turbojet-derived hot section the best choice for all types.
In the 1970s the CCGT combined cycle appears (half of UK electricity now comes from these). As these are clean-slate designs, and not dependent on thrust, they too favour single combustors and may be reverse flow.
Gas turbine articles here could use a lot of improvement. The thermodynamics isn't bad, but the engineering tends to get dominated by the aircraft spotters. Andy Dingley (talk) 00:33, 13 February 2019 (UTC)
Right :-) The PT6 is interesting, I'm glad I know all that now! I think the article does quite well at explaining the 'different' layout until we get to the 'folded' combustor where it's let down by the links to combustion chamber - combustors, where perhaps under the heading of "air flow paths" something more could be said? Searching here for reverse-flow turbine then among lots of helicopter engines I have found recent turbofans (e.g.) the quite up to date https://en.wikipedia.org/wiki/GE_Honda_HF120 Pratt & Whitney Canada PW600 as well as the larger, slightly older but still relatively current Lycoming ALF 502 - all said to have reverse flow combustors. Then again the General Electric H80 is described as 'reverse flow' in more of a PT6 sense. 86.150.255.227 (talk) 20:49, 13 February 2019 (UTC)

Uses fresh air[edit]

What's the reason for emphasising that the atmospheric air is fresh? It seems a redundant word so could do with a qualifier. Cheers.Pieter1963 (talk) 17:07, 29 April 2019 (UTC)

Agree. Looks like it is "atmospheric" in the context of where the turbine is used and "fresh" in the sense that it replenishes that which is ejected, but "fresh atmospheric" suggests something beyond that. DMacks (talk) 18:13, 29 April 2019 (UTC)

Improvements I hope[edit]

Improvements to help the average reader, (not those who already know the subject). "area" delete redundant, "gas generator" - tells reader what the 3 components do, "between 1 and 2 above" replace, "often used" clarify 4th component always used and tell reader why, match words better to pictorial arrangements by mentioning nozzle. "greater power to mass/volume ratio" maybe, but not for the average reader.Pieter1963 (talk) 18:40, 30 April 2019 (UTC)

Possible improvement[edit]

Ref. existing "A fourth component is often used to increase efficiency (turboprop, turbofan), to convert power into mechanical or electric form (turboshaft, electric generator), or to achieve greater power to mass/volume ratio (afterburner)." This sentence relates to the pictorial arrangements shown in the lead, mentioning 4 of the 5, as possible fourth components ie the coverage is almost complete except it makes no mention of number 1. Is it worth clarifying that number 1 is also a possible fourth component?Pieter1963 (talk) 20:06, 1 May 2019 (UTC)

"greater power to mass/volume ratio" This article is a very basic overview of the gas turbine. What is the justification for using a textbook expression for the afterburner in the lead for this article? Surely there is something better which is more appropriate, thrust? To illustrate, we will wait a lifetime waiting to hear someone say "the plane's not getting off the ground fast enough. The engine needs more power for its mass/volume ratio." Keep it simple whilst still using correct terminology. Comment anyone? CheersPieter1963 (talk) 14:17, 2 May 2019 (UTC)
Since the expression is not revisited anywhere in the text we could explain it with a statement in the appropriate place, eg "reduces the diameter and weight compared to a non-afterburning engine which produces the same maximum thrust".Pieter1963 (talk) 17:09, 2 May 2019 (UTC)
The way I see it, the gas turbine has only 3 essential components - the compressor, the combustion chamber (aka gas generator) and the turbine. The output is purely thrust. This thrust can then be used as:
  1. a pure jet (turbo-jet),
  2. captured by another turbine and mechanically fed to a propeller (turbo-prop), electric generator (turbo-shaft), helicopter rotor (turbo-shaft), wheels (as in some tanks and a very few cars),
  3. a combination of both jet and capture by another turbine (high/low bypass turbo-fan),
  4. as the compressor stage of an afterburner.
The so-called fourth component is really just the method in which the thrust is harnessed for useful work.  Stepho  talk  22:41, 2 May 2019 (UTC)

Align lead wording to MOS:LEAD|WP:MOSLEAD[edit]

ref "Provide an accessible overview", current wording is overly specific, uses difficult-to-understand terminoloy (eg what is jet-engine power? What is relevance of engine mass?), uses unnecessary mathematical formula.

Suggest replacing "to achieve greater power to mass/volume ratio" with "to increase maximum thrust of basic engine", which is verbatim from an industry publication. Feedback anyone? Cheers.Pieter1963 (talk) 21:13, 4 May 2019 (UTC)

Here is a suggestion:

A gas turbine, also called a combustion turbine, is a type of continuous combustion, internal combustion engine. The main elements common to all gas turbine engines are:

  1. An upstream rotating gas compressor;
  2. A downstream turbine on the same shaft;
  3. A combustor in between compressor and turbine.

A fourth component is often used to increase efficiency (turboprop, turbofan), to convert power into mechanical or electric form (turboshaft, electric generator), or to achieve greater thrust- or power-to-weight ratio (afterburner).


Links should take care of your concern. The lead should reflect the article content. It is not to be a simple-worded introduction to the topic. Ariadacapo (talk) 06:51, 5 May 2019 (UTC)
Nailed it, thanks. I would prefer a compressor - combustor - turbine order.--Marc Lacoste (talk) 14:50, 5 May 2019 (UTC)
Agreed. Except power-to-weight ratio is not applicable to jet engines (not measurable), it's thrust-to-weight, which is a Figure of merit for a jet engine. The link mentions power, as in maximum power, but that refers to the pilot asking for more fuel, hence more gas power generated in the main combustor or afterburner, ie inside the black box. The black box output is thrust. The airframer buys thrust, hence definition for SFC. Pieter1963 (talk) 16:59, 5 May 2019 (UTC)

Suggestion for lead improvement[edit]

The last edit added "or reheating". I presume this refers to inter-turbine reheat in which case "power-to-weight ratio" needs to be changed to efficiency. Also it needs a link for clarity (it doesn't seem to be covered in the article). Please let me know.Pieter1963 (talk) 14:39, 7 May 2019 (UTC)

Reheat
Yes, I mean inter-turbine reheat, like illustrated in the attached thumbnail. It is used to increase specific power, or work ratio. Increases in efficiency are not the point, efficiency may decrease. --Ariadacapo (talk) 15:14, 7 May 2019 (UTC)
To achieve greater power-to-weight ratio on reheating engines This has never been a reason for reheating. ..in power generation gas turbine power-to-weight ratio does not play a critical role and reheating gives increased power output at the expense of weight, eg addition of large-volume combustion chamber.
As regards specific power, work ratio and reduced efficiency this was the state of affairs 50 years ago. Early assessments of the benefit of reheat concluded: reheat markedly increases specific work output at the expense of efficiency and needs heat-exchange and reheating is employed principally to increase the work ratio and specific work output. (written pre-1971).
The lead will better reflect developments which have taken place since 1990 by recognizing efficiency as the driver. ...significant efficiency improvement (eg the 1995 ABB GT-9 engine increased from 32% to 40.5%) can be achieved by introducing the reheat concept and ..this (HP turbine followed by LP combustion chamber and LP turbine) standard efficiency improvement method.. and Reheat, an effective method for substantially increasing the thermal efficiency (Written 2018).
The lead sentence in question is also not consistent in so far as it introduces an arrangement not shown in the accompanying thumbnails. Nor does it have a link for reheating. I had to guess what it was. Please note that most readers will assume that it is just the British term for afterburning. This would be a non-conformance to the MOS which requires precise wording to avoid misunderstandings.
Suggestions for improvement: 1. reword such that efficiency is reflected as the reason for reheating and 2. add the reheat thumbnail to the other five and 3. add a link or, failing that, an in-line citation so the reader knows where to find what reheating means in this particular context.Pieter1963 (talk) 19:48, 8 May 2019 (UTC)
What are you up to here? Your text reads like you are loudly lecturing everybody in the room. Please focus on the text you would like to see, by proposing a draft. Ariadacapo (talk) 05:39, 9 May 2019 (UTC)
Here is the draft for proposed change:
" A fourth component is often used to increase efficiency (on turboprops and turbofans), to convert power into mechanical or electric form (on turboshafts and electric generators), or to achieve greater thrust-to-weight ratio on afterburning engines. Cheers.Pieter1963 (talk) 17:06, 9 May 2019 (UTC)
Here is an alternative if you would still like to keep mention of reheating. "A fourth component is often used to increase efficiency (on turboprops and turbofans), occaisonally to increase efficiency using inter-turbine reheat on electric generators, to convert power into mechanical or electric form (on turboshafts and electric generators), or to achieve greater thrust-to-weight ratio on afterburning engines." I would also suggest including the reheat thumbnail. Pieter1963 (talk) 17:36, 10 May 2019 (UTC)
I removed the mention of reheating on the account that it does not appear in the article body. (I’m skipping over the rest of the discussion, which really does not interest me). Ariadacapo (talk) 18:31, 10 May 2019 (UTC)