Talk:Gas turbine

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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)

Contents

[edit] Brayton Cycle

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)

[edit] Quasiturbine

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)

[edit] Capstone turbines

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)

[edit] Confusing

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)

[edit] External links to manufacturers

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)

[edit] removed images

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)

[edit] GTS Finnjet correction

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)

[edit] Marine Gas Turbine Usage

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)

[edit] Tank use information

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)