Experimental Study of Three-Dimensional Natural Convection at High Rayleigh Number

摘要

Natural convection heat transfer measurements and flow visualization experiments were performed in a three-dimensional (cubical) test cell in water. The heat transfer data were reduced to dimensionless correlations which help elucidate the mechanisms of heat transfer at high Rayleigh number in a three-dimensional enclosure. Results of the flow visualization experiments further supported the hypothesized heat transfer mechanisms. When the top and bottom surfaces of the enclosure are adiabatic, heat is transferred by two-dimensional boundary layers which remain laminar at Rayleigh numbers as high as 7 x 10 exp 10 . Heating the test cell bottom produces plume-like structures (thermals) which transport the heat from the bottom and modify the boundary layers and, therefore, heat transfer from the vertical walls. (ERA citation 08:050961)