Talk:Steam turbine

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Contents 1 Repeated content 2 Poor wording 3 Jonal turbine 4 A few errors on this page 5 Electric drive 6 Reversible, Reversing 7 about 86% ... 8 Unclear

[edit] Repeated content

The two longest paragraphs are about problems with turbines. I think they should be merged--some content is repeated. DonSiano 13:54, 3 August 2005 (UTC).

[edit] Poor wording

I'm just a layman. The sentence below (from the "Impulse Turbines" section) does not make grammatical sense. Please, someone correct it so it says what is intended:

The steam leaving the moving blades is a large portion of the maximum velocity of the steam when leaving the nozzle.

Perhaps this what is meant:

The steam leaving the moving blades still retains a large portion of the velocity it had after leaving the nozzle.

--216.165.154.93 21:14, 2 November 2006 (UTC) [JM]

I put in your wording. -- Kjkolb 06:34, 23 June 2007 (UTC)

[edit] Jonal turbine

I came across the term "Jonal turbine" while working on the article. I do not think that this is the correct spelling, as I have never heard of it and "Jonal turbine" in quotes does not get a single hit except for Wikipedia and its mirrors. Many of the turbine names next to Jonal turbine in the article were misspelled. I was able to find the proper spelling for all of the others, but I did not find anything on any of the variations of "Jonal" that I could think of. If the proper spelling cannot be found, I suggest that it be removed from the article. -- Kjkolb 06:34, 23 June 2007 (UTC)

I have never heard of a turbine of this name and couldn't find anything. Removed from article.--Dj245 00:19, 19 October 2007 (UTC)

[edit] A few errors on this page

Although I don't have time to look up references for my information, I have been exposed to steam turbines in school and noticed a few errors on this page. The first being the listing of impulse and reaction turbines. The turbines listed are all water turbine stages. I can't remember all 4 types of steam stages, but I know they include parsons and delaval stages. I believe Parsons is purely reactive and delaval is a cross between the two.

The other error is in the section talking about a steam turbine for ships propulsion. If you look into the wiki article on ships they talk about propulsion and how a steam turbine is less efficient than a comparable diesel. The main reason steam is used on a commercial ship is if the ship by nature of it's cargo (such as a liquified natural gas ship) has a source of fuel available that it can't burn in a diesel engine it will use that to drive a steam turbine. The other use is in a nuclear ship where the only way to extract the power is to produce steam. Although a steam turbine takes up less space that a comparable diesel engine, the equipment required to run the turbine (boiler and steam piping) takes up considerably more space along with the added dangers of having high pressure superheated steam. —Preceding unsigned comment added by 72.90.173.42 (talk) 12:33, 21 January 2008 (UTC)

I agree with the turbine types, it looks like someone scoured the web and inserted any old thing they found. However, I think it may be possible to run a diesel on LNG tanker boil-off gas. Does natural gas autoignite at a reasonably obtainable temperature and pressure? I also agree when looking at the whole plant, steam is almost always larger than a comparable diesel. Very large diesels need their own auxiliaries and heat exchangers though which increases the size and complexity of the plant.--Dj245 (talk) 05:51, 24 January 2008 (UTC)

The wiki for ships meantions the technology being developed, and slowly implemented for operating an ICE via LNG boil off gasses, but it sounds like it is a relatively new technology. ICEs generally require some modifications to operate on a different fuel type than they are designed for, but it is possible. Diesel engines are inherently complex, but a slow speed diesel will have a similar shaft speed to the most efficient propeller speed for a large ship, whereas a steam turbine requires a pretty significant reduction gear setup.161.154.235.245 (talk) 16:26, 28 January 2008 (UTC)

Bold text

[edit] Electric drive

I don't think I'm the person to do it, but the section on speed reduction should mention electric drive. This was used in some US battleships between the two world wars. There were certain advantages: one turbine running flat out is more efficient than four running at quarter-power, but the opposite is true for electric motors driving marine propellers, and full power was available for going astern. Philip Trueman (talk) 20:06, 18 February 2008 (UTC)

Electric drive is not a method of gear reduction. It is an alternative method of power transmission and control. It is currently used in certain British naval ships, but has little to do with reduction gears.--Dj245 (talk) 01:39, 19 February 2008 (UTC)

I didn't say anything about reduction gears. Neither the article nor the section is about gears, nor should it be. The section is about speed reduction. The point is that the optimum speed for a steam turbine is mis-matched with the optimum speed for a marine propeller, and there is more than one way of overcoming the mismatch. Reduction gearing is one way; sometimes double reduction gearing is used. At the time the Royal Navy began applying reduction gearing the US Navy began applying electric drive (to battleships, at any rate). The two navies had different priorities, with the Royal Navy emphasising efficiency at full speed and the US Navy, with the vast distances of the Pacific in mind, emphasising efficiency at slower but more economical speeds. One figure I've seen quoted is that electric drive gave a fuel saving of about 20% at those speeds, for the reason I've explained above. Philip Trueman (talk) 15:09, 19 February 2008 (UTC)

[edit] Reversible, Reversing

The first paragraph seems to imply a relation between a reversible process, and the physical reversing of a marine turbine. The two or not related. Perhaps, the last line of this paragraph referring to a reversing marine steam turbine should be removed from the introduction for clarity. SFKatUMO (talk) 17:19, 2 March 2008 (UTC) —Preceding unsigned comment added by SFKatUMO (talk • contribs) 16:42, 2 March 2008 (UTC)

I agree and have removed the sentence. Also, the matter probably didn't deserve mention in the introduction. Thincat (talk) 15:59, 7 April 2008 (UTC)

Humm. I agree the unfortunate juxtaposition had to be fixed, but the sentence removed still made a valid point. It was usual, in the days before reversible-pitch propellers, for ships to be equipped with several turbines per shaft - say, one for full power, one for slow-speed cruising, and a reversing turbine. The reversing turbine wasn't reversible, it just turned the shaft the other way. For reciprocating engines there were ways of getting the engines to turn the other way, but a reversible steam turbine would be a nightmare to design, hence the need for a dedicated turbine. The history of reversing turbines goes right back to Parsons' Turbina. Electric drive also provided another solution to the problem. Perhaps room could be found to make this point elsewhere in the article? Philip Trueman (talk) 14:10, 8 April 2008 (UTC)

Yes, I don't find the article too clear on the "reversing" aspect and more detail (though maybe not in the introduction) would be welcome. I have just now moved the notion of "reversible" out of the introduction and into the section on efficiency. This might clear the ground generally, and for reintroducing "reversing" near the top, if anyone thought it beneficial. Thincat (talk) 08:17, 15 April 2008 (UTC)

[edit] about 86% ...

The article says about 86% of the world's electricity is generated using steam turbines. There's a [citation needed] tag, and there are some cites I could put in for this: [1] [2] These pages just seem to pull the figure out of thin air too, though. Are there any authoritative sources available that speak to the other 14% of electricity or mention some real research?--Martinship (talk) 09:10, 29 April 2008 (UTC)

You could also determine what percentage of sources are Coal, Nuclear, Oil-fired, Geothermal, and biomass (usually woodchips). If it isn't PV solar, wind, or gas turbine, its a steam turbine.--Dj245 (talk) 16:42, 30 April 2008 (UTC)

... and then you'd still have to apportion the power generated by gas-fired combined-cycle systems. Philip Trueman (talk) 18:44, 13 May 2008 (UTC)

[edit] Unclear

I don't think this article is anywhere near clear enough about how the increasingly larger set of blades interact with one another. There is too much jargon and not enough dead simple explanation. This is why I came to this article and it really doesn't do the typical good job I've come to expect of a wikipedia article. I know that high speed steam blows on the blades and that turns a shaft but why and how do the blades interact? Johnor (talk) 20:38, 29 April 2008 (UTC)

I don't think they do, in the way you mean. There are two interleaved sets of 'discs' of blades: one fixed, and one rotating. As the steam expands its thermal energy is converted to kinetic energy which is directed onto the moving blades. The blades speed up, the steam slows down, and then the next stage of expansion occurs. Does that help? Philip Trueman (talk) 18:42, 13 May 2008 (UTC)