Experiments on natural convection heat transfer in low aspect ratio enclosures
Abstract
Natural convection heat transfer in rectangular enclosures of aspect ratio less than and equal to one is investigated experimentally. The experiments covered a range of Rayleigh numbers between 10,000 and 4 x 10 to the 7th, aspect ratios between 0.043 and 1.0, and Prandtl numbers between 5.5 and 19,280 using water and various silicone oils. In case of aspect ratio equal to 1.0 the Nusselt number was found to be nearly independent of Pr. For aspect ratio equal to 0.2, Nu was noticeably influenced by Pr in a certain range of Ra due to the behavior of secondary cells. Nu for water in low aspect ratio enclosures was found to be proportional to the 0.3 power of the Rayleigh number in the boundary layer regime, but there was an indication that Nu becomes eventually proportional to approximately the 0.25 power of the Rayleigh number at higher Ra as in the case of aspect ratio equal to 1.0.
 Publication:

AIAA, 16th Thermophysics Conference
 Pub Date:
 June 1981
 Bibcode:
 1981thph.confR....K
 Keywords:

 Convective Heat Transfer;
 Enclosures;
 Fluid Dynamics;
 Free Convection;
 Low Aspect Ratio;
 Prandtl Number;
 Rayleigh Number;
 Liquids;
 Nusselt Number;
 Oils;
 Silicon Compounds;
 Space Commercialization;
 Temperature Distribution;
 Water;
 Fluid Mechanics and Heat Transfer