Experimental Study on the Air-Side Performance of a Multipass Parallel and Counter Cross-Flow L-Footed Spiral Fin-and-Tube Heat Exchanger

Abstract

This study conducted experiments on the air-side performance of novel L-footed spiral fin-and-tube heat exchangers that were faced with airflow at high Reynolds numbers 000). The examined heat exchangers have a multipass paralleland-counter cross-flow type of water flow arrangement. This flow arrangement is a combination of the parallel cross-flow and the counter cross-flow. This type of water flow arrangement may be the best fit for the reverse-flow system, because it can provide constant heat-exchange effectiveness for every flow reversal direction at the same airflow rate. Ambient air was used as a working fluid on the air side and hot water for the tube side. This way the effect of the number of tube rows on the heat transfer and friction characteristics of L-footed spiral fin-and-tube heat exchangers was clearly observed. The effect of the fin's outside diameter on the pressure drop was also studied. The results show that the number of tube rows has no significant effect on the air-side heat transfer or on friction characteristics at high Reynolds numbers. However, the fin's outside diameter shows a significant effect on the pressure drop. The pressure drop increases as the fin's outside diameter increases for the same number of tube rows.

A review on the thermal hydraulic characteristics of the air-cooled heat exchangers in forced convection

“…The correlations for the Colburn factor and the friction factor were presented in the study. In the similar study on the same experimental setup Pongsoi et al (2012a) studied the effect of number of tube rows along with the variation in the fin height. The effect of the number of tube rows was similar as were found in the previous study.…”

Air-side performance of serrated welded spiral fin-and-tube heat exchangers

“…Further details about the data reduction can be seen from Pongsoi et al [11][12][13][14][15][16]. The efficiency of a radial fin with rectangular profile is based on the derivation of Gardner [20], i.e.,…”

“…In this study, the serrated welded spiral fin-and-tube heat exchangers having Z-shape tube arrangements and the 2 tube rows are investigated by using the experimental apparatus of Pongsoi et al [11][12][13][14][15] and Pongsoi and Wongwises [16], including the water flow loop, air-flow supply, measuring instruments, and data acquisition. The detailed geometrical parameters of the test sections are shown according to Table 1.…”

“…The working fluids are ambient air and hot water for air-side and water-side, respectively. Moreover, the detailed descriptions of the relevant components can be seen from [11][12][13][14][15][16]. For the experimental conditions, as shown in Table 2, the temperature and flow rate of waters are fixed while varying the ambient air flow rate in range of high Reynolds numbers (4000-15,000).…”

The use of computational fluid dynamics in analysing the performance of an elliptical annular fin

“…1,2 The experiments on heat exchanger with annular fins of various fins spacings and different air speeds under the free and forced convection were conducted by Han-Taw Chen et al, [3][4][5][6] and they reported that the value of heat transfer coefficient increases and efficiency decreased with increase in fin spacing and air speed values. Parinya pangs et al 7 conducted the experiments on the air-side performance of novel L footed spiral fin and tube heat exchangers. They concluded that the number of tube rows had no significant effect on the air side heat transfer and the pressure drop increases as the fin outside diameter increased for the same number of tube rows.…”