Performance evaluation of twisted-tape insert induced swirl flow in a laminar thermally developing heat exchanger

Lim, Kwok Yoong; Hung, Yew Mun; Tan, Boon Thong

doi:10.1016/j.applthermaleng.2017.04.134

Cited by 64 publications

(25 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This figure indicates that the increasing free convection effects due to the increased heat flux caused the Colburn j-factors and friction factors in the laminar flow regime to increase [41,44,66,68]. At a laminar Reynolds number of 500, the Colburn j-factor enhancement was 103% when the heat flux was increased from 1.35 kW/m 2 to 2 kW/m 2 .…”

Section: Heat Fluxmentioning

confidence: 90%

“…A comprehensive literature review on twisted tape inserts indicated that previous studies concentrated mainly on the laminar flow regime for Reynolds numbers between 13 and 3 000 [2,5,15,[37][38][39][40][41][42][43][44][45] or the turbulent flow regime for Reynolds numbers greater than 3 000 [4,29,33,[46][47][48][49][50][51] and not specifically on the transitional flow regime [52][53][54][55]. Up to now, only Wongcharee and Eiamsa-ard [15] (in the laminar flow regime) and Eiamsa-ard and Promvonge [4] (in the turbulent flow regime), considered alternating clockwise and counter clockwise twisted tape (CCCTT)…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Heat transfer and pressure drop characteristics of alternating clockwise and counter clockwise twisted tape inserts in the transitional flow regime

Abolarin

Everts

2019

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

The purpose of this study was to experimentally investigate the heat transfer and pressure drop characteristics in a smooth circular tube with alternating clockwise and counter clockwise twisted tape (CCCTT) inserts. The CCCTT inserts were fabricated from copper plate strips with a length, width and thickness of 450 mm, 18 mm and 1 mm respectively. The strips were twisted to obtain a twist ratio of 5 and 12 strips were joined longitudinally so that a clockwise direction twisted tape insert was connected to a counter clockwise direction twisted tape. The assembling was at connection angles of 0°, 30° and 60°, to form CCCTT inserts with an overall length of 5.27 m. The CCCTT inserts were placed in a smooth circular copper tube with an inner diameter of 19 mm. Water was used as the test fluid and experiments were conducted at constant heat fluxes of 1.35, 2, 3 and 4 kW/m 2 between Reynolds numbers of 300 and 11 404. This covered the laminar, transitional and turbulent flow regimes. Specific attention was given to the identification of the transitional flow regime with the CCCTT inserts and the influence of the connection angle and heat flux on the transitional flow regime. It was found that both the start and the end of the transitional flow regime were influenced by the connection angle and the heat flux. When different connection angles were compared it was found that an increase in connection angle enhanced the heat transfer in the transitional flow regime. An increase in heat flux significantly enhanced the heat transfer in the laminar flow regime and delayed transition. Heat transfer and pressure drop correlations were developed to predict the experimental data in the laminar, transitional and turbulent regimes as a function Reynolds number, modified Grashof number and connection angle.

show abstract

Section: Heat Fluxmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Heat transfer and pressure drop characteristics of alternating clockwise and counter clockwise twisted tape inserts in the transitional flow regime

Abolarin

Everts

2019

International Journal of Heat and Mass Transfer

View full text Add to dashboard Cite

show abstract

“…Moreover, Akhavan-Behabadi et al [15] tried to investigate the heat transfer increment due to twisted tape inserts in R-134a condensers. Lim et al [16] in 2017 studied the heat transfer augmentation of laminar flow in heat exchangers equipped with twisted tape inserts and they found that the induced swirling flow will increase the heat transfer rate of the system. In their work, several various operational factors are taken into account.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation of enhancing influence of Al2O3 nanoparticles on the convective heat transfer in a tube equipped with twisted tape inserts

2021

View full text Add to dashboard Cite

In this study, the heat transfer rate of Al 2 O 3 /Water nanofluid flow in a tube with twisted tape inserts is examined, experimentally. The twisted tape insert can cause a swirling region in the fluid flow which will enhance the heat transfer coefficient. On the other hand, the twisted tape inserts have a great influence on the pressure drop. It is known that nanoparticles and twisted tape inserts may both increase the heat transfer rate of the fluid. Thus, in this study, it is tried to demonstrate the combined effect of both phenomena, experimentally. In this way, the Al 2 O 3 /Water nanofluid is used as the carrier liquid in a tube equipped with various twisted tape inserts of different pitches and twist ratios. Moreover, the influence of nanoparticles' volume fractions was studied in the turbulent regime of a tube with the constant temperature boundary condition.

show abstract

“…The results indicate a higher heat exchanger efficiency by using twisted tape inserts so that the highest PEC number was equal to 1.42 and was reported under the empirical conditions. The use of twisted tapes in a double-tubes at various pitch ratios was examined by Lim et al [ 27 ]. They predicted heat transfer characteristics for different Reynolds number values.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

Ghalambaz

Arasteh

Mashayekhi³

et al. 2020

Nanomaterials

View full text Add to dashboard Cite

This study investigated the laminar convective heat transfer and fluid flow of Al2O3 nanofluid in a counter flow double-pipe heat exchanger equipped with overlapped twisted tape inserts in both inner and outer tubes. Two models of the same (co-swirling twisted tapes) and opposite (counter-swirling twisted tapes) angular directions for the stationary twisted tapes were considered. The computational fluid dynamic simulations were conducted through varying the design parameters, including the angular direction of twisted tape inserts, nanofluid volume concentration, and Reynolds number. It was found that inserting the overlapped twisted tapes in the heat exchanger significantly increases the thermal performance as well as the friction factor compared with the plain heat exchanger. The results indicate that models of co-swirling twisted tapes and counter-swirling twisted tapes increase the average Nusselt number by almost 35.2–66.2% and 42.1–68.7% over the Reynolds number ranging 250–1000, respectively. To assess the interplay between heat transfer enhancement and pressure loss penalty, the dimensionless number of performance evaluation criterion was calculated for all the captured configurations. Ultimately, the highest value of performance evaluation criterion is equal to 1.40 and 1.26 at inner and outer tubes at the Reynolds number of 1000 and the volume fraction of 3% in the case of counter-swirling twisted tapes model.

show abstract

Performance evaluation of twisted-tape insert induced swirl flow in a laminar thermally developing heat exchanger

Cited by 64 publications

References 36 publications

Heat transfer and pressure drop characteristics of alternating clockwise and counter clockwise twisted tape inserts in the transitional flow regime

Heat transfer and pressure drop characteristics of alternating clockwise and counter clockwise twisted tape inserts in the transitional flow regime

Experimental investigation of enhancing influence of Al2O3 nanoparticles on the convective heat transfer in a tube equipped with twisted tape inserts

Investigation of Overlapped Twisted Tapes Inserted in a Double-Pipe Heat Exchanger Using Two-Phase Nanofluid

Contact Info

Product

Resources

About