Description

This study presents the airside performance of the fin-andtube heat exchangers having plain fin geometry with a larger diameter tube (Dc = 16.88 mm). The effect of tube row and fin pitch on the airside are examined. It is found that the effect of fin pitch on the Colburn j factor is negligible at N = 2. However, a notable drop of heat transfer performance is seen when the number of tube row is increased to eight.The effect of tube row on the friction factor is almost negligible. However, unlike those of friction factor, the Colburn j factor reveals a different characteristic subject to the influence of the number of tube row. If the fin pitch is above a certain threshold value (Fp = 3~4 mm), the influence of tube row on Colburn j-factor is very small. However, if the fin pitch is below this threshold value, the Colburn j-factor exhibits a considerable drop with the rise of the number of tube row. This phenomenon is especially pronounced at low Reynolds number region. It is likely that this phenomenon is related to the complex flow field interactions between the tube row and fin surfaces. The Wang et al.’s correlation (2000) gives fairly good predictive ability against the present friction factor but under-predicts the j-factor slightly. Based on the present database, a correlation is developed that can describe the j-factor with a 3.99% mean deviation and the f-factor with a 2.83% deviation.

Units: SI

Citation: ASHRAE Transactions, vol. 114, pt. 1, New York 2008

Product Details

Published:

2008

Number of Pages:

8

File Size:

1 file , 2.4 MB

Product Code(s):

D-NY-08-043