Numerical Analysis of Tube Heat Exchanger with Perforated Star-Shaped Fins

Abstract

This article discusses the possibility of further reducing the mass of the heat exchanger with stainless steel star-shaped fins while achieving good heat transfer performance. For this purpose, we perforated the fins with holes Ø2, Ø3, and Ø4 mm. Applying computational fluid dynamics (CFD) numerical analysis, we determined the influence of each perforation on the characteristics of the flow field in the liquid–gas type of heat exchanger and the heat transfer for the range of Re numbers from 2300 to 16,000. With a reduction in the mass of the fins to 17.65% (by Ø4 mm), perforated fins had greater heat transfer from 5.5% to 11.3% than fins without perforation. A comparison of perforated star-shaped fins with annular fins was also performed. Perforated fins had 51.8% less mass than annular fins, with an increase in heat transfer up to 26.5% in terms of Nusselt number.

Heat Transfer Intensification in a Heat Exchanger by Means of Twisted Tapes in Rib and Sawtooth Forms

“…The empirical correlations for the Nusselt number, friction factor, and aerothermal performance index developed from experimental results of TTRSs for all sawtooth angles (α) are shown as follows. Nu = 0.049Re 0.762 Pr 0.4 (tan(α/90)) 0.098 (18) f = 11.178Re −0.492 (tan(α/90)) 0.075 (19) API = 4.392Re −0.136 (tan(α/90)) 0.073 (20) Comparisons between the experimental data and the predictions are illustrated in Figure 8a-c. These figures show that the predictions are adequately accurate.…”

“…The desired augmented heat transfer rate is counterbalanced by an undesirably increased pressure drop [8][9][10][11][12][13]. In addition, turbulators are also presented in the forms of extended surfaces, for example, louvered and wavy fins [14,15], serrated fins [16,17], star-shaped fins [18], and perforated fins [19,20].…”

A review on the modification of circular fin and tube heat exchangers through new innovative fin shapes

“…The effect of perforated star-shaped finned tubes with different diameter holes of Ø2, Ø3, and Ø4 mm on performance was numerically analyzed by [11] with 2300<Re<16000 using CFD. At a temperature of 288k, air passes over the fins at speeds varying from 1 to 7m/s.…”

Three-dimensional assessment of thermal-hydraulic behaviour in heat exchangers fitted by wavy annular fins

“…Zaidan et al [13] examined and compared the heat transfer and flow properties of a one-row annular fin-and flat-tube with three different types of perforations. Recently, Bošnjaković and Muhič [14] combined the passive techniques of star-shaped fins and perforated fins to further improve the efficiency of annular fins. Some researchers show that the eccentric finned-tube technique significantly improves the HE performance under the same total thermal exchange surface area.…”