convection


convection
convectional, adj.
/keuhn vek"sheuhn/, n.
1. Physics. the transfer of heat by the circulation or movement of the heated parts of a liquid or gas.
2. Meteorol. the vertical transport of atmospheric properties, esp. upward (distinguished from advection).
3. the act of conveying or transmitting.
[1615-25; < LL convection- (s. of convectio) a bringing together. See CONVECT, -ION]

* * *

Process by which heat is transferred by movement of a heated fluid such as air or water.

Most fluids expand when heated. They become less dense and more buoyant, and so rise. The heated molecules eventually cool, become more dense, and sink. This repeated process sets up convection currents that account for the uniform heating of the air in a room or water in a kettle. Air convection can be forced by a fan, and water convection by a pump. Atmospheric convection currents can be set up by local heating effects such as solar radiation or contact with cold surfaces. Such currents are usually vertical and account for atmospheric phenomena such as clouds and thunderstorms.

* * *

      process by which heat is transferred by movement of a heated fluid such as air or water.

      Natural convection results from the tendency of most fluids to expand when heated—i.e., to become less dense and to rise as a result of the increased buoyancy. Circulation caused by this effect accounts for the uniform heating of water in a kettle or air in a heated room: the heated molecules expand the space they move in through increased speed against one another, rise, and then cool and come closer together again, with increase in density and a resultant sinking.

      Forced convection involves the transport of fluid by methods other than that resulting from variation of density with temperature. Movement of air by a fan or of water by a pump are examples of forced convection.

      Atmospheric convection currents can be set up by local heating effects such as solar radiation (heating and rising) or contact with cold surface masses (cooling and sinking). Such convection currents primarily move vertically and account for many atmospheric phenomena, such as clouds and thunderstorms.

* * *


Universalium. 2010.

Look at other dictionaries:

  • convection — [ kɔ̃vɛksjɔ̃ ] n. f. • 1877; lat. convectum, de vehere « transporter » 1 ♦ Phys. Transport d une grandeur physique (masse, courant électrique, chaleur) dans un fluide par un déplacement de l ensemble de ses molécules. Convection libre ou… …   Encyclopédie Universelle

  • Convection — Con*vec tion, n. [L. convectio, fr. convehere to bring together; con + vehere to carry.] 1. The act or process of conveying or transmitting. [1913 Webster] 2. (Physics) A process of transfer or transmission, as of heat or electricity, by means of …   The Collaborative International Dictionary of English

  • convection — (n.) 1620s, from L. convectionem (nom. convectio) the act of carrying, from convect , pp. stem of convehere to carry together, from com together (see COM (Cf. com )) + vehere to carry (see VEHICLE (Cf. vehicle)) …   Etymology dictionary

  • convection — ► NOUN ▪ transference of mass or heat within a fluid caused by the tendency of warmer and less dense material to rise. DERIVATIVES convect verb convectional adjective convective adjective. ORIGIN Latin, from convehere, from vehere carry …   English terms dictionary

  • convection — [kən vek′shən] n. [L convectio < pp. of convehere, to bring together < com , together + vehere, to carry, bear] 1. a transmitting or conveying 2. a) the mass movement of parts of a fluid within the fluid because of differences in the… …   English World dictionary

  • Convection — This figure shows a calculation for thermal convection in the Earth s mantle. Colors closer to red are hot areas and colors closer to blue are cold areas. A hot, less dense lower boundary layer sends plumes of hot material upwards, and likewise,… …   Wikipedia

  • Convection — La convection est un mode de transfert qui implique un déplacement de matière dans le milieu, par opposition à la conduction thermique ou diffusion de la matière. La matière est advectée (transportée conduite, mais ces termes sont en fait… …   Wikipédia en Français

  • convection — [[t]kənve̱kʃ(ə)n[/t]] N UNCOUNT Convection is the process by which heat travels through air, water, and other gases and liquids. [TECHNICAL] ...clouds which lift warm, moist air by convection high into the atmosphere. ...convection currents …   English dictionary

  • convection — noun Etymology: Late Latin convection , convectio, from Latin convehere to bring together, from com + vehere to carry more at way Date: circa 1623 1. the action or process of conveying 2. a. the circulatory motion that occurs in a fluid at a… …   New Collegiate Dictionary

  • convection — Conveyance of heat in liquids or gases by movement of the heated particles, as when the layer of water at the bottom of a heated pot rises or the warm air of a room ascends to the ceiling. [L. con veho, pp. vectus, to carry or bring together] * * …   Medical dictionary


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.