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
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).