Inscrição na biblioteca: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

NATURAL CONVECTION HEAT TRANSFER WITHIN ENCLOSURES AT REDUCED PRESSURES

Get access (open in a dialog) DOI: 10.1615/IHTC8.3020
pages 1483-1488

Resumo

Natural convection heat transfer in air within enclosures has been investigation over the pressure range of 2,670 to 86,180 Pa (20−646.4 mm Hg). Dimensionless correlations have been generated from the data. The best correlation found was: NuL = .142 Ra.31 where L is the hypothetical gap width. The Rayleigh number in the experiments ranged over 1 × 103 − 2 × 106. These equations, obtained from low pressure data, represent very accurate correlations at very low Rayleigh numbers. The geometries used were heated isothermal cylinders and cubes mounted concentrically within a cooled isothermal cubical enclosure. Temperature profiles at four positions (0°, 34°, 80° and 160° from the upward vertical) were measured for the cylinder-cube case. The thickening of the boundary layer at low pressures and the region of constant temperature between the bodies at high Rayleigh number were clearly observed.