Heat transfer and pressure changes due to a large temperature difference across an enclosed vertical air layer
Abstract
The TRACE2D Code has been used to obtain nonBoussinesq results from transient, compressible and twodimensional calculations using Sutherland law conductivity and viscosity property variations for air. These free convection results are limited to the laminar flow region. The aspect ratio A of the vertical air layer, with adiabatic top and bottom walls, is taken to be unity or greater, and the Rayleigh number Ra based on the layer width is as large as 10 to the 7th power when A = 1. The results are valid for large temperature differences between the hot and cold isothermal walls, epsilon = sub T(h)  sub T(c) or = 0.6, where the limitation is due to the Sutherland law accuracy. The various flow regimes are defined in terms of epsilon, A and Ra and correlations are developed for the Nusselt number and pressure in terms of these parameters. It is shown that, with proper nondimensionalization, much of the vast body of literature concerning Nusselt number correlations and vertical temperature stratification for the Boussinesq case (which is asymptotically approached here for epsilon 1) can be used where epsilon is not small.
 Publication:

6th Bien. CUBE (Computer Use by Engineers) Symposium
 Pub Date:
 August 1984
 Bibcode:
 1984cube.symp...61C
 Keywords:

 Boundary Layers;
 Computer Programs;
 Convection;
 Heat Transfer;
 Temperature Gradients;
 Correlation;
 Laminar Flow;
 Rayleigh Number;
 Viscosity;
 Fluid Mechanics and Heat Transfer