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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

The improved prediction of turbulent convection

Get access (open in a dialog) DOI: 10.1615/IHTC12.1930
6 pages

要約

A simple algebraic expression has been devised that predicts without any explicit empiricism the Nusselt number for fully developed turbulent forced convection in round tubes, parallel-plate channels, and circular concentric annuli for arbitrary thermal boundary conditions on the wall(s), all values of Re, and all values of Pr greater than 0.45. A complementary expression for values of Pr less than 1.7 incorporates one arbitrary (empirical) exponent. These two expressions are made up of only four elements: the limiting solution, Nu0, for Pr = 0; a particular solution, Nu1, for Pr = Prt; the asymptotic solution, Nu for Pr → ∞ ; and the parameter, Prt/Pr. Nu0 and Nu1 incorporate some empiricism by virtue of a semitheoretical correlating equation for the local turbulent shear stress, but the resulting uncertainty in the predicted values of Nu0, Nu1, and Nu is completely negligible (less than 1%). The greatest uncertainty arises from the necessity of utilizing a semitheoretical expression for Prt/Pr, but again the resulting uncertainty in Nu is completely negligible (less than 1.5%). A critique is presented for these expressions and their elements in terms of experimental data, numerically computed values, and prior correlating equations.