Talk:Heat engine
From Wikipedia, the free encyclopedia
 |
This article is within the scope of WikiProject Physics, which collaborates on articles related to physics. |
| ??? | This article has not yet received a rating on the assessment scale. [FAQ] |
| ??? | This article has not yet received an importance rating within physics. |
|
Help with this template Please rate this article, and then leave comments to explain the ratings and/or to identify its strengths and weaknesses. |
|
The difference between Cycle type and engines needs to be split apart. The Diesil cycle can be run completely differently from the diesil engine. Ericsson created a Diesil cycle engine that ran on external combustion. The diesil cycle doesn't require diesil fuel and can have an air fuel mixture instead of fuel injection. The Otto Cycle can be either 2 or 4 stroke.Eric Norby
Would it be reasonable to add the tropical cyclone as another example of a heat engine? Presumably under the vapor power cycle heading.
Cyclones: I'm not an expert on cyclones, but I would guess it is roughly an example of one of the types already mentioned? If anyone knows more about it, it's a good example to add. Mat-C 17:40, 10 July 2005 (UTC)
Changed: moved carnot out of vapour cycle. Nothing about carnot is specifically phase change that I know of (and nothing on its page suggests so).Mat-C 17:40, 10 July 2005 (UTC)
I've removed this from the Ericsson Cycle page, would be nice to include something like it here: Thermodynamically, the Ericsson cycle is more similar to the Stirling and Carnot cycles. All use isothermal compression and expansion at the hot and cold temperatures. To transition the gas between the hot and cold temperatures Carnot uses adiabatic compression and expansion, Stirling uses constant volume regeneration, and Ericsson uses constant pressure regeneration. All are theoretically capable of Carnot efficiency if there are no losses. Both Brayton and Ericsson can be realized by the same simple machine, a turbine compander. A Brayton cycle with regeneration and an infinite number of stages of intercooling and reheat is equivalent to the Ericsson cycle. Mat-C 18:08, 12 July 2005 (UTC)
Contents |
[edit] What is the purpose of this page?
This page appears to be a mishmash of highly technical discussion and lists. The lists are incomplete and the technical discussion is mostly covered more usefully in other articles (such as carnot cycle). Would it be best to make this page a simple description with suitable off links to more detail; should we try to make the list complete; is it useful to have diagrams?
The article doesn't make the relationship between heat engines and heat pumps clear, and it doesn't make the point that all (almost?) energy transformations involve the carnot efficiency (e.g. batteries, solar panels, lights).
I'm happy to spend a while cleaning it up, but I am not getting an feeling for what really belongs here. njh 08:36, 4 February 2006 (UTC)
[edit] Agree - need for an overhaul
Nathan - I agree with your comments about this page. I would propose a reasonable simple explanation of what a heat engine is, and relationship to a heat pump. This article might refer to heat/work cycles in nature but I think the emphasis should be on man-made machines. It would be good to have list of links to cycles, and also to pages referring to example machines. Agree that it would be best to keep cycles and machines separate.
It would be great if this article could also be mirrored for heat pumps, which is also in need of some attention. mike 17:45, 17 March 2006 (UTC)
[edit] removed 'photon cycle'
I removed "photon cycle" and the only example listed under it, solar sail. A solar sail operates by converting radiation pressure into mechanical energy. That makes it a type of engine other than a heat engine. --Delirium 06:30, 10 September 2006 (UTC)
[edit] reference to new article: Heat engine classifications
I created a new article with the goal to develop a basic list that is logical, conceptually clear, and inclusive of all practicable approaches to building a machine to convert heat energy into mechanical energy. KYcrank 00:32, 6 November 2006 (UTC)
[edit] Agree with first two comments - This article is poor
I've been interested in heat engines for some time, and I have never heard anyone make the argument (especially after just having pointed out that heat engines work on a heat differential, and extract power from that differential alone) that internal combustion engines are heat engines of any kind-- steam, gasoline, diesel... These engines are, by no possible stretch of definitions I can think of, operating by differential in heat. I was writing in here several examples of why it's past ridiculous to include many of these engine types as heat engines, but it's not even worth doing: the statement itself is self-evidently ludicrous. 68.99.213.231 05:05, 4 January 2007 (UTC) Andy R.
[edit] New heat engine model should be incorporated
There is a new paper published in the "International Journal of Energy Research" (http://dx.doi.org/10.1002/er.1312) that details a new heat engine model that accurately reproduces the efficiencies of Otto, Brayton, and Stirling cycle engines. This new model should be covered under this topic. —The preceding unsigned comment was added by 69.244.46.21 (talk) 14:18, 7 March 2007 (UTC).
I hacked this discussion from the middle of the article Ϙ 18:49, 4 June 2007 (UTC). [-->I think this section needs correction. MIT's Professor Gyftopoulos seems pretty smart: http://web.mit.edu/nse/people/faculty/gyftopoulos.html
He slams the endoreversible theory in a paper titled: "On the Curzon–Ahlborn efficiency and its lack of connection to power producing processes".
Abstract: "Because some physicists continue to defend the nonexistent theory of finite time thermodynamics, additional incontrovertible experimental and theoretical evidence is provided about its irrationality and nonreality."
Curzon-Ahlborn efficiency is the endoreversible theory. ---Steve]
>The Carnot Cycle limit cannot be reached with any gas-based cycle, but engineers have worked out at least two ways to possibly go around that limit
Helllooo, nurse... Either very poor choice of wording or suggestion that those engineers are trying to exceed Carnot cycle efficiency limit. THAT I sorta would like to see, coz it's pretty equivalent to creating perpetuum mobile. Except not going to happen. —Preceding unsigned comment added by 87.110.96.68 (talk) 23:01, 14 March 2008 (UTC)
