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Encyclopedia

From Wikipedia, the free encyclopedia

Steam phase eruption of Castle Geyser in Yellowstone Park
A temperature-versus-entropy diagram for steam
A Mollier enthalpy-versus-entropy diagram for steam

Steam is vaporized water. It is a transparent gas. At standard temperature and pressure, pure steam (unmixed with air, but in equilibrium with liquid water) occupies about 1,600 times the volume of an equal mass of liquid water. In the atmosphere, the partial pressure of water is much lower than 1 atm, therefore gaseous water can exist at temperatures much lower than 100 °C (212 °F) (see water vapor and humidity).

In common speech, steam most often refers to the visible white mist that condenses above boiling water as the hot vapor mixes with the cooler air. This mist consists of tiny droplets of liquid water. Pure steam emerges at the base of the spout of a steaming kettle where there is no visible vapor.

Contents

Saturated steam

Saturated steam is steam at equilibrium with liquid water [1]. It defines the boundary between wet steam and superheated steam on the temperature-enthalpy diagram.

Superheated steam

Main article: Superheated steam

Superheated steam is steam at a temperature higher than its boiling point at a given pressure. For superheating to take place one of two things must occur. Either all of the liquid water must have evaporated or, in the case of steam generators (boilers), the saturated steam must be conveyed out of the steam drum before superheating can occur, as steam can not be superheated in the presence of liquid water.[2]

There are three stages of heating to convert liquid water to superheated steam. First the liquid water’s sensible temperature (the property that can be measured with a thermometer) is raised. Then latent heat (this heat does not raise the temperature of the fluid) is added. After all of the liquid is evaporated or the saturated steam is taken from the steam drum sensible heat is again added superheating the steam.

Industrial uses

Steam engines and steam turbines

A steam engine uses the expansion of steam in order to drive a piston or turbine to perform mechanical work. The ability to return condensed steam as water-liquid to the boiler at high pressure with relatively little expenditure of pumping power is important. Engineers use an idealised thermodynamic cycle, the Rankine cycle, to model the behavior of steam engines.

Steam turbines are often used in the production of electricity.

Condensation of steam to water often occurs at the low-pressure end of a steam turbine, since this maximizes the energy efficiency, but such wet-steam conditions have to be limited to avoid excessive turbine blade erosion.

Energy storage

In other industrial applications steam is used for energy storage, which is introduced and extracted by heat transfer, usually through pipes. Steam is a capacious reservoir for thermal energy because of water's high heat of vaporization.

Electricity generation

In the U.S., more than 86% of electricity is generated using steam as the working fluid, nearly all by steam turbines.

Cogeneration

In electric generation, steam is typically condensed at the end of its expansion cycle, and returned to the boiler for re-use. However in cogeneration, steam is piped into buildings through a district heating system to provide heat energy after its use in the electric generation cycle. The world's biggest steam generation system is the New York City steam system which pumps steam into 100,000 buildings in Manhattan from seven cogeneration plants.[3]

Sterilization

An autoclave, which uses steam under pressure, is used in microbiology laboratories and similar environments for sterilization.

Agricultural use

In agriculture, steam is used for soil sterilization to avoid the use of harmful chemical agents and increase soil health.

Domestic uses

Steam's capacity to transfer heat is also used in the home: for cooking vegetables, steam cleaning of fabric and carpets, and heating buildings. In each case, water is heated in a boiler, and the steam carries the energy to a target object. "Steam showers" are actually low-temperature mist-generators, and do not actually use steam.

Steam tables

Steam tables are tables of thermodynamic data for water/steam. They are often used by engineers and scientists in design and operation of equipment where thermodynamic cycles involving steam are used. Additionally, thermodynamic phase diagrams for water/steam, such as a temperature-entropy diagram or a Mollier diagram shown in this article, may be useful.

Steam explosion

When liquid water comes in contact with a very hot substance (such as lava, or molten metal) it can flash into steam almost instantaneously; this is called a steam explosion. Such an explosion was probably responsible for much of the damage in the Chernobyl accident and for many so-called foundry accidents.

See also

References

  1. ^ Singh, R Paul. (2001). Introduction to Food Engineering. Academic Press. ISBN 978-0-12-646384-2.
  2. ^ http://www.spiraxsarco.com/resources/steam-engineering-tutorials/steam-engineering-principles-and-heat-transfer/superheated-steam.asp
  3. ^ Carl Bevelhymer, "Steam", Gotham Gazette, November 10, 2003

External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

STEAM (0. Eng. steam, vapour, smoke, cf. Du. stoom; the origin is unknown), water-vapour. Dry steam is steam free from mechanically mixed water particles; wet steam, on the other hand, contains water particles in suspension. Saturated steam is steam in contact with liquid water at a temperature which is the boiling point of the water and condensing point of the steam; superheated steam is steam out of contact with water heated above this temperature. For theoretical considerations see Vaporization, and for the most important application see Steam Engine; also Water.


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Strategy wiki

Up to date as of January 23, 2010
(Redirected to Category:Steam article)

From StrategyWiki, the free strategy guide and walkthrough wiki

Steam
The console image for Steam.
Manufacturer Valve Corporation
Active 2002—present
Total Games unknown (106 present)
← (none) (none) →
Popular guides
  1. Mount&Blade
  2. Grand Theft Auto: San Andreas
  3. Grand Theft Auto IV
  4. Grand Theft Auto: Vice City
  5. Battlestations: Midway
  6. Call of Duty 4: Modern Warfare
  7. Counter-Strike: Source
  8. Portal
  9. Grand Theft Auto III
  10. Team Fortress 2

Steam is a content-delivery system designed and run by Valve Corporation. Although initially only used for Valve's games, it now has over 200 games from Valve and from third parties. Similarly, it was originally only a content-delivery system, but now has instant messaging with friends (and in-game support for this), community pages, support for game media such as preview movies, and inbuilt support for modding tools such as Hammer.

Steam Community

A comparison of two gamers' Team Fortress 2 statistics on Steam Community.

On September 12, 2007, Valve released the Steam Community; a new system allowing gamers to have their own page in the community and network socially with other gamers. The system allows gamers to have friends, belong to groups, and compare their game statistics to others'; recent Valve games such as those in The Orange Box have integrated statistics systems which detail many aspects of a player's scoring online. As well as being able to view statistics through Steam, people can also view people's profiles and statistics through a web browser, by going to steamcommunity.com.

The Steam Community update also introduced new features to the instant messaging system in Steam, including voice and avatar support, as well as more useful notification of a contact's game status and support for multi-user chats.

Pages in category "Steam"

The following 106 pages are in this category, out of 106 total.

A

B

C

D

E

  • Empires: Dawn of the Modern World

F

G

G cont.

  • Grand Theft Auto: Vice City
  • Gun

H

  • Half-Life
  • Half-Life 2
  • Half-Life 2: Deathmatch
  • Half-Life 2: Episode One
  • Half-Life 2: Episode Two
  • Half-Life: Blue Shift
  • Half-Life: Opposing Force
  • Hitman: Blood Money
  • Hitman: Codename 47

I

K

L

M

N

  • Need for Speed: Undercover

O

  • Oddworld: Abe's Oddysee
  • On the Rain-Slick Precipice of Darkness: Episode One
  • On the Rain-Slick Precipice of Darkness: Episode Two
  • The Orange Box

P

Q

R

S

T

U

V

  • Vampire: The Masquerade - Bloodlines

W

X

  • X-COM: Apocalypse
  • X-COM: Terror from the Deep

Z


Gaming

Up to date as of February 01, 2010

From Wikia Gaming, your source for walkthroughs, games, guides, and more!

Steam is an online distribution by Valve Software. It is a way for them to deliver their content online, straight to the consumers. It started in 2002 as a method of patching, but became much more within the next few years. Because this process of selling and delivering online cuts out game store retailers and game publishers, Valve became involved in a legal dispute with Vivendi Universal, their publisher. Vivendi Universal argued that Valve was going against their publishing agreement.

Currently, many games such as Half-Life, Half-Life 2, Day of Defeat, Counter-Strike, and more are available over Steam. Half-Life 2 even requires online authorization via Steam to work. There are also games by other developers released or planned for release on Steam, like Rag Doll Kung Fu and SiN Episodes.

External links

  • Steam Powered
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Smallwikipedialogo.png This page uses content from Wikipedia. The original article was at Steam. The list of authors can be seen in the page history. As with Wikia Gaming, the text of Wikipedia is available under the Creative Commons Attribution-Share Alike 3.0 (unported) license. The content might also be available under the terms of the GNU Free Documentation License.

This article uses material from the "Steam" article on the Gaming wiki at Wikia and is licensed under the Creative Commons Attribution-Share Alike License.

Simple English

Steam is the name given to water when it is a gas. Steam is always seen as a string of cloudy translucent mist. But, that is only the result of the steam condensing on the surface of dust in the air, which means the steam that you touch would not be very hot. The steam that is really 100 degrees Celsius is invisible.

When the pressure of the atmosphere is 1013 mbar (this is about the average pressure for a place which is at sea level), water will boil (turn into steam) at 100 degrees Celsius.

100 degrees Celsius is the same temperature as 212 degrees Fahrenheit, 80 degrees Réaumur and 373.15 Kelvin.








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