NATURAL-CONVECTION IN A HEMISPHERICAL ENCLOSURE HEATED FROM BELOW

Citation
Y. Shiina et al., NATURAL-CONVECTION IN A HEMISPHERICAL ENCLOSURE HEATED FROM BELOW, International journal of heat and mass transfer, 37(11), 1994, pp. 1605-1617
Citations number
32
Categorie Soggetti
Mechanics,"Engineering, Mechanical",Thermodynamics
ISSN journal
00179310
Volume
37
Issue
11
Year of publication
1994
Pages
1605 - 1617
Database
ISI
SICI code
0017-9310(1994)37:11<1605:NIAHEH>2.0.ZU;2-I
Abstract
Natural convection in a hemisphere heated from below was studied exper imentally. Correlation between heat transfer rate and Rayleigh number was obtained on a hemispherical surface over wide parameter ranges: 10 (6) less-than-or-equal-to Ra less-than-or-equal-to 6 x 10(10) and 6 le ss-than-or-equal-to Pr less-than-or-equal-to 13000. The exponent of Nu against Ra changes from 1/4 to 1/3 at about Ra approximately 10(9). F low patterns in a hemisphere were observed for 2 x 10(5) less-than-or- equal-to Ra less-than-or-equal-to 2 x 10(9) and 6 less-than-or-equal-t o Pr less-than-or-equal-to 13000. The patterns were classified into se veral flow regimes. i.e. steady circulating flow, flow with periodic t hermal plumes, flow with irregular thermal plumes and turbulent flow r egime. Experimental results show that fully turbulent flow regime occu rs at Ra approximately 10(9).