دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the rise and fall of liquids in small-diameter tubes or tubelike spaces, caused by the combined action of surface tension (cohesion) and wetting (adhesion). See capillary pressure.

n: the attractive force between the same kinds of molecules (i.e., the force that holds the molecules of a substance together). exchangers. In more complex installations, a tube bundle is used instead of a coil.

n: The attractive forces between molecules of the same kind, that is, the force that holds the molecules of a substance together.


a force that holds fluids and sand grains together. The force is generated by attraction at the molecular level. Cohesion is often used to describe sand grains stuck together by a low viscosity fluid such as oil or water, although this is better explained

n: See cohesion.

n: the cohesion of the individual particles of a given materal (i.e., its ability to deform or its resistance to flow).

n: The viscosity of a non-reversible fluid, in poises, for a certain time interval at a given pressure and temperature.

a fluid’s ability to deform and flow and its general cohesion to itself.

n: the curved upper surface of a liquid column, concave when the containing walls are wet by the liquid (negative meniscus) and convex when not (positive meniscus).

a phenomena between a liquid and a solid surface created by adhesion and cohesion forces. The meniscus may be upward where adhesion forces are stronger than cohesion or downward when cohesion forces are stronger.

n: the tendency of liquids to maintain as small a surface as possible. It is caused by the cohesive attraction between the molecules of liquid.

n: Surface free energy that exists between a liquid and air. Surface tension can be observed as a curved meniscus in a small tube of the liquid. This energy barrier prevents a liquid (such as water) from spontaneously mixing with air to form a foam. To make

a measurement of the difficulty of moving a fluid past another fluid (see interfacial tension). The resistance is created by the cohesion forces between the liquid molecules. The forces make it more difficult to pass fluids past a surface. Surface tension

n: a measure of the resistance of a fluid to flow. Resistance is brought about by the internal friction resulting from the combined effects of cohesion and adhesion. The viscosity of petroleum products is commonly expressed in terms of the time required for a specific volume of the liquid to flow through a capillary tube of a specific size at a given temperature.

n: A property of fluids and slurries that indicates their resistance to flow, defined as the ratio of shear stress to shear rate.

a measurement of the internal resistance of a fluid to flow against itself. Expressed as the ratio of shear stress to shear rate.