# Transport phenomena

Transport phenomena

In physics, chemistry, biology and engineering, a transport phenomenon is any of various mechanisms by which particles or quantities move from one place to another. The laws which govern transport connect a flux with a "motive force". Three common examples of transport phenomena are diffusion, convection, and radiation. The science of transport phenomena is a great complement to rheological study of Newtonian fluids.

There are three main categories of transport phenomena:
* Heat transfer,
* Mass transfer, and
* Fluid dynamics (or momentum transfer)

An important principle in the study of transport phenomena is analogy between phenomena.For example, mass, energy, and momentum can all be transported by diffusion:
* The spreading and dissipation of odors in air is an example of mass diffusion.
* The conduction of heat in a solid material is an example of heat diffusion.
* The drag (physics) experienced by a rain drop as it falls in the atmosphere is an example of momentum diffusion (the rain drop loses momentum to the surrounding air through viscous stresses and decelerates).The transport of mass, energy, and momentum can also be affected by the presence of external sources:
* An odor dissipates more slowly when the source of the odor remains present.
* The rate of cooling of a solid that is conducting heat depends on whether a heat source is applied.
* The gravitational force acting on a rain drop counteracts the drag imparted by the surrounding air.All these effects are described by the generic scalar transport equation.

The generalized method adopted for solving transport phenomena problems start with quantity analysis for any given system as:

(Rate of quantity IN) - (Rate of quantity OUT) + (Rate of Production of the quantity) = (Rate of Accumulation of the Quantity)
The transferring quantity here can be momentum, energy or mass. For example, during momentum transport analysis for a freely falling film of a Newtonian liquid, gravitational force is counted as a factor increasing momentum in the system; and the momentum dissipation will be in the form of fluid moving out of the system, and work losses. [R. Byron Bird, Warren E. Stewart, Edwin N. Lightfoot, "Transport Phenomena" (1960) John Wiley & Sons, New York, ISBN 0-471-07392-X, pp.42-48]

The same equations governing convection in heat transfer can be applied to convection in mass transfer. When studying complex transport phenomena problems one must use tools from continuum mechanics and tensor calculus and often problems can be expressed as partial differential equations.

In solid state physics, the motion and interaction of electrons, holes and phonons are studied under "transport phenomena". [J. M. Ziman, "Electrons and Phonons: The Theory of Transport Phenomena in Solids (Oxford Classic Texts in the Physical Sciences)"]

* Constitutive equation
* Continuity equation
* Wave propagation
* Pulse
* Action potential

Resources

*cite web
title = Some Classical Transport Phenomena Problems with Solutions - Fluid Mechanics
url= http://www.syvum.com/eng/fluid/

*cite web
title = Some Classical Transport Phenomena Problems with Solutions - Heat Transfer
url= http://www.syvum.com/eng/heat/

*cite web
title = Some Classical Transport Phenomena Problems with Solutions - Mass Transfer
url= http://www.syvum.com/eng/mass/

* [http://teaching.matdl.org/ Transport Phenomena Archive] in the Teaching Archives of the Materials Digital Library Pathway

References

Wikimedia Foundation. 2010.

### Look at other dictionaries:

• Transport Phenomena — infobox book name=Transport Phenomena image caption= author=Bird, R.B., Stewart, W.E. and Lightfoot, E.N. language=English subject= Transport Phenomena publisher=John Wiley Sons release date=1960 (First Edition) media type=Hardback pages=780 isbn …   Wikipedia

• transport phenomena — pernašos reiškiniai statusas T sritis Standartizacija ir metrologija apibrėžtis Negrįžtamieji reiškiniai, kurių metu fizikinėje sistemoje pernešamas elektros krūvis, masė, energija, judesio kiekis. atitikmenys: angl. transfer phenomena; transport …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• transport phenomena — pernašos reiškiniai statusas T sritis chemija apibrėžtis Negrįžtamieji reiškiniai, kurių metu fizikinėje sistemoje pernešamas elektros krūvis, masė, energija. atitikmenys: angl. transport phenomena rus. явления переноса …   Chemijos terminų aiškinamasis žodynas

• Transport (disambiguation) — Transport most likely refers to: :* Transport, the movement of people and goods from place to place, and related terms such as: ** transport , used (especially in military contexts) to mean a vehicle to carry supplies or personnel, , e.g.… …   Wikipedia

• transport phenomenon — ▪ physics       in physics, any of the phenomena involving the movement of various entities, such as mass, momentum, or energy, through a medium, fluid or solid, by virtue of nonuniform conditions existing within the medium. Variations of… …   Universalium

• Generic scalar transport equation — The generic scalar transport equation is a general partial differential equation that describes transport phenomena such as heat transfer, mass transfer, fluid dynamics (momentum transfer), etc. A general form of the equation is: frac{partial… …   Wikipedia

• Passive transport — means moving biochemicals and other atomic or molecular substances across membranes. Unlike active transport, this process does not involve chemical energy, because, unlike in an active transport, the transport across membrane is always coupled… …   Wikipedia

• transfer phenomena — pernašos reiškiniai statusas T sritis Standartizacija ir metrologija apibrėžtis Negrįžtamieji reiškiniai, kurių metu fizikinėje sistemoje pernešamas elektros krūvis, masė, energija, judesio kiekis. atitikmenys: angl. transfer phenomena; transport …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• phénomènes de transport — pernašos reiškiniai statusas T sritis Standartizacija ir metrologija apibrėžtis Negrįžtamieji reiškiniai, kurių metu fizikinėje sistemoje pernešamas elektros krūvis, masė, energija, judesio kiekis. atitikmenys: angl. transfer phenomena; transport …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• Co-transport — Co transport, also known as coupled transport or secondary active transport, refers to the simultaneous or sequential passive transfer of molecules or ions across biological membranes in a fixed ratio. Permitting one ion or molecule to move from… …   Wikipedia