ISSN Online: 2377-424X
International Heat Transfer Conference 3
EXPERIMENTAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFER IN SIMPLE AND OBSTRUCTED HOHIZONTAL ANNULI
摘要
Natural convection heat transfer in horizontal annuli and in enclosures formed by helical and axial
spacers in annuli has been examined experimentally over the following range of parameters:
4 × 104 ≤
RaDi
≤ 4.7 × 1010, 2 ≤ D0/Di ≤ 4 and 0.645 ≤ Pr ≤ 1.32. The overall heat transfer data on
simple annuli are correlated by:−
log kc/k = 0.0794 + 0.0625 log X + 0.0154 (log X)2
where X &361; RaDi[1−(Di/D0)]6.5
It would appear that spacers of the type examined in this investigation have only negligible effect on the overall heat transfer in annuli. To examine this rather unexpected result and to obtain a better understanding of the mechanism of convective heat transfer, the flow behaviour in simple and obstructed annuli has been studied using the schlieren technique.
log kc/k = 0.0794 + 0.0625 log X + 0.0154 (log X)2
where X &361; RaDi[1−(Di/D0)]6.5
It would appear that spacers of the type examined in this investigation have only negligible effect on the overall heat transfer in annuli. To examine this rather unexpected result and to obtain a better understanding of the mechanism of convective heat transfer, the flow behaviour in simple and obstructed annuli has been studied using the schlieren technique.