Browsing by Author "Pongsoi, Parinya"

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Effect of fin pitches on the air-side performance of crimped spiral fin-and-tube heat exchangers with a multipass parallel and counter cross-flow configuration
(2011-04-01)
Pongsoi, Parinya
;
Pikulkajorn, Santi
;
Wang, Chi-Chuan
;
Wongwises, Somchai
;
機械工程學系
This study investigates the effect of fin pitches and fin materials on the air-side performance of crimped fin-and-tube heat exchangers in the range of high Reynolds numbers (4000-13000). The test samples are made from copper and aluminium with different fin pitches (f(p) = 3.2, 4.2 and 6.2 mm). It is found that the proposed simple average effectiveness equation from the pure counter and parallel circuitry arrangement can well represent the effectiveness-NTU relationship for the current z-shape arrangement. The experimental results reveal that the fin pitch casts insignificant effect on the heat transfer characteristics (Colburn j factor). However, a detectable rise of the friction factor is seen when the fin pitch is increased to f(p) = 6.2 mm. On the other hand, the effect of fin material on the airside performance is negligible. (C) 2010 Elsevier Ltd. All rights reserved.
Effect of number of tube rows on the air-side performance of crimped spiral fin-and-tube heat exchanger with a multipass parallel and counter cross-flow configuration
(2012-01-31)
Pongsoi, Parinya
;
Pikulkajorn, Santi
;
Wang, Chi-Chuan
;
Wongwises, Somchai
;
機械工程學系
The air-side performance of crimped spiral fin and tube heat exchangers at high Reynolds number (3000-13,000) is investigated in this study. The test heat exchangers have a new type of multipass parallel and counter cross-flow water flow arrangement which is a combination of parallel cross-flow and counter cross-flow. The test samples are made from copper and aluminium with different number of tube rows (N-row = 2, 3, 4 and 5). The effects of number of tube rows and fin material on the heat transfer and friction characteristics are studied. The results show that no significant effect for either number of tube rows or fin materials on the heat transfer performance is found at high Reynolds number. In addition, the correlation of the air-side performances of this type of the heat exchangers at high Reynolds number is developed for industrial applications. (c) 2011 Elsevier Ltd. All rights reserved.