Fluid Mechanics, Heat Transfer and Mass Transfer
In the context of fluid mechanics. the Bejan number is the dimensionless pressure drop along a channel of length :
where
- is the dynamic viscosity
- is the momentum diffusivity
In the context of heat transfer. the Bejan number is the dimensionless pressure drop along a channel of length :
where
- is the dynamic viscosity
- is the thermal diffusivity
The Be number plays in forced convection the same role that the Rayleigh number plays in natural convection.
In the context of mass transfer. the Bejan number is the dimensionless pressure drop along a channel of length :
where
- is the dynamic viscosity
- is the mass diffusivity
For the case of Reynolds analogy (Le = Pr = Sc = 1), it is clear that all three definitions of Bejan number are the same.
Read more about this topic: Bejan Number
Famous quotes containing the words fluid, heat, transfer and/or mass:
“In place of a world, there is a city, a point, in which the whole life of broad regions is collecting while the rest dries up. In place of a type-true people, born of and grown on the soil, there is a new sort of nomad, cohering unstably in fluid masses, the parasitical city dweller, traditionless, utterly matter-of-fact, religionless, clever, unfruitful, deeply contemptuous of the countryman and especially that highest form of countryman, the country gentleman.”
—Oswald Spengler (1880–1936)
“Two wooden tubs of blue hydrangeas stand at the foot of the stone steps.
The sky is a blue gum streaked with rose. The trees are black.
The grackles crack their throats of bone in the smooth air.
Moisture and heat have swollen the garden into a slum of bloom.
Pardie! Summer is like a fat beast, sleepy in mildew....”
—Wallace Stevens (1879–1955)
“If it had not been for storytelling, the black family would not have survived. It was the responsibility of the Uncle Remus types to transfer philosophies, attitudes, values, and advice, by way of storytelling using creatures in the woods as symbols.”
—Jackie Torrence (b. 1944)
“Commercial jazz, soap opera, pulp fiction, comic strips, the movies set the images, mannerisms, standards, and aims of the urban masses. In one way or another, everyone is equal before these cultural machines; like technology itself, the mass media are nearly universal in their incidence and appeal. They are a kind of common denominator, a kind of scheme for pre-scheduled, mass emotions.”
—C. Wright Mills (1916–62)