Dm. Mceligot et al., TURBULENT NATURAL-CONVECTION FROM A VERTICAL CYLINDER TO AN ARRAY OF COOLED TUBES, Journal of heat transfer, 115(4), 1993, pp. 928-937
In order to determine whether available correlations are adequate to t
reat a complicated, turbulent natural convection problem encountered i
n industrial practice, experiments were conducted by resistively heati
ng a slender, vertical cylinder centered inside a concentric perforate
d tube, which was, in turn, surrounded by an array of three larger-dia
meter cooled tubes. The ratio of the test section temperature to the c
ooling tube temperature was varied up to 2.6; and the Rayleigh number,
based on tube diameter and properties evaluated at the cooling tube t
emperature, ranged from 2.9 x 10(4) to 9.2 x 10(5). Results indicate t
hat the convective heat transfer parameters for the perforated tube ar
e about 15 percent higher than for the smooth bare tube centered in th
e same position relative to the array. The Nusselt number for convecti
ve heat transfer across the annulus between the heated test section an
d the perforated tube corresponded approximately to parallel laminar f
low (i. e., Nu(s) almost-equal-to 1).