Natural convection heat transfer in horizontal rod-bundle enclosures
- Uinv. of Tennessee, Knoxville, TN (United States)
Natural convection heat transfer in enclosed horizontal N x N arrays (N = 3, 5, and 7) of electrically heated rods with a pitch-to-diameter ratio (P/d) of 1.35 has been experimentally investigated. Each array was positioned in an isothermal square enclosure with a width-to-diameter ratio (W/d) of 20.6. Pressurized air or helium was used as the working fluid. It was observed that the bottom-row rods were relatively insensitive to increases in the array size, as they exhibit only slight temperature variations, but the top-row rods demonstrated substantial temperature increases. Natural convection correlations in the form of Nusselt number (Nu{sub d})as a function of modified Rayleigh number (Ra{sub d}{sup *})were obtained for each rod in each array. The correlations cover three flow regimes of conduction, transition, and convection in the range of 6.45 < Ra{sub d}{sup *} < 3.08 x 10{sup 5}. A generalized enclosure Nusselt number was correlated as a function of enclosure modified Rayleigh number and the array size (N). Comparison of the data with previous numerical prediction showed that this correlation may be readily used to obtain a conservative estimate of the maximum temperature in the arrays with N = 3, 5, 7, and 9. 14 refs., 12 figs., 1 tab.
- OSTI ID:
- 380766
- Journal Information:
- Journal of Heat Transfer, Journal Name: Journal of Heat Transfer Journal Issue: 3 Vol. 118; ISSN 0022-1481; ISSN JHTRAO
- Country of Publication:
- United States
- Language:
- English
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