Heat transfer and thermal performance characteristics of heat exchanger tube fitted with perforated twisted-tapes

Abstract

Twisted tape insert was applied as a swirling flow generator for the passive heat transfer enhancement in the present work. The influences of the perforated twisted tapes (PTs) on the heat transfer, pressure loss and thermal performance characteristics were investigated experimentally. The experiments were performed under uniform wall heat flux condition by using PTs with y/W = 3, 4 and 5, d/W = 0.11, 0.14 and 0.17 and s/W = 0.4, 0.6 and 0.8 where y is a twist length, d is a perforation hole diameter, s is a spacing between holes (pitch) and W is a tape width. The experimental results reveal that Nusselt number increased with decreasing s/W and y/W and increasing d/W. For the present range, the maximum heat transfer was obtained by utilizing the tape with s/W = 0.4, d/W = 0.17 and y/W = 3, which is higher than those obtained from the plain tube with and without typical twisted tape by around 27.4 and 86.7%, respectively. In addition, the empirical correlations for Nusselt number, friction factor and thermal performance are also proposed in the present paper.

Numerical investigation of heat transfer and fluid flow of water through a circular tube induced with divers' tape inserts

“…Its thermal performance factor is up to 1.43 times that of the tube with a plain twisted tape. The Nusselt numbers of the numerical results, the novel correlations of the present work and the established correlation of Thianpong et al [46] were found to have a very reasonable agreement. This was also the case for the friction factor.…”

“…The Nusselt number and friction factor obtained from the correlations developed in the present work agree with those of their numerical results with a discrepancy of 2.52% and 4.23% respectively. The Nusselt number obtained from the correlation of Thianpong et al [46] is in a very good agreement with those of the correlations developed in the present work with a discrepancy of 2.21%, and for the friction factor it is 3.01%. TAECT_Thianpong et al [46] (a) (b)…”

“…The Nusselt number obtained from the correlation of Thianpong et al [46] is in a very good agreement with those of the correlations developed in the present work with a discrepancy of 2.21%, and for the friction factor it is 3.01%. TAECT_Thianpong et al [46] (a) (b)…”

“…Comparisons were made among the numerical results of the present work, the new correlations developed in the present work, and the correlations proposed by Thianpong et al [46] for the Nusselt number ( Fig. 10 (a)) and friction factor ( Fig.…”

The current situation of the study on twisted tape inserts in pipe exchangers

“…To balance the heat transfer and pressure drop, the perforated twisted tape (PTs) was proposed by Thianpong et al (2012). The data results showed that in the range studied, PTs consistently provide higher Nusselt numbers than the typical twisted tapes due to the extra fluid turbulence around the tube wall caused by the holes on the tapes.…”