Nusselt Number


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Nusselt number

[′nu̇s·əlt ‚nəm·bər]
(physics)
A dimensionless number used in the study of mass transfer, equal to the mass-transfer coefficient times the thickness of a layer through which mass transfer is taking place divided by the moleculor diffusivity. Symbolized Num ; NNu m . Also known as Sherwood number (NSh ).
(thermodynamics)
A dimensionless number used in the study of forced convection which gives a measure of the ratio of the total heat transfer to conductive heat transfer, and is equal to the heat-transfer coefficient times a characteristic length divided by the thermal conductivity. Symbolized NNu .
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Nusselt Number

 

a dimensionless parameter that characterizes the intensity of convective heat exchange between the surface of a body and a flow of gas (or liquid). It is named after the German physicist W. Nusselt (1882–1957). The Nusselt number Nu = αl/λ, where α = Q/(S · ΔT) is the heat-exchange coefficient, Q is the heat transfer across the surface of the body per unit time, ΔT > O is the difference of temperature between the surface of the body and the gas (or liquid) measured outside the boundary layer, S is the area of the surface, l is a characteristic dimension, and λ is the coefficient of thermal conductivity of the gas.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
For case I, the fluid recirculation is reduced to the mid-height of the cavity, which gives a minimum local Nusselt number at Y ~ 0.55 with two peaks on either sides of this position.
Figure 19 presents the effect of the rotating parameter A on the local Nusselt number. The local Nusselt number decreases with increase in A with the effect being more momentous towards the steady-state flow.
The influence of volume concentration ratios as a function of temperature on the Nusselt number is shown in Figure 13(b).
Nusselt Number. Nondimensional Nusselt number [Nu.sub.S] = -([partial derivative][[theta].sub.S]/[partial derivative]R)[|.sub.R=1] is obtained from temperature profile (18) as
In heat transfer at a boundary (surface) within a fluid, the Nusselt number (Nu) is the ratio of convective to conductive heat transfer across (normal to) the boundary.
The Churchill and Bernstein (1977) relation can be used to calculate the Nusselt number across a separate cylinder for a wide range of Reynolds and Peclet numbers ([10.sup.2] < Re < [10.sup.7], Pe > 0.2):
Thus, the stream-wise velocity distributions at the module inlets (see Figure 9) and normalized pressure drop Figure 4 and module average Nusselt number for each module (Table 2) confirm the existence of periodically fully developed flow downstream of the second module.
For the characterization of the heat transfer of the cabin and the TM, a Nusselt number (Nu) is defined.
The numerical values for the skin friction, the local Nusselt number are presented and examined.