Thermo-hydraulic analysis for a novel eccentric helical screw tape insert in a three dimensional tube

Zade, Navid Moghadas; Akar, Shima; Rashidi, Saman; Esfahani, Javad Abolfazli

doi:10.1016/j.applthermaleng.2017.06.036

Cited by 53 publications

(14 citation statements)

References 32 publications

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“…The corresponding bulk Reynolds numbers for the start, Recrb, and end, Reqtb, of the transitional flow regime in terms of the friction factors were obtained by replacing the Gr*(x) in Eqs. (13) and (14) with the bulk modified Grashof number, Gr*b. The ranges and performance of Eqs.…”

Section: Start and End Of The Transitional Flow Regimementioning

confidence: 99%

“…The ranges and performance of Eqs. (13) and (14) are summarised in Table 4. This table indicates that the start and end of transitional flow regime of both the Colburn j-factor and friction factor results could be determined within 6%.…”

Section: Start and End Of The Transitional Flow Regimementioning

confidence: 99%

“…These turbulators include coatings and/or roughness on the inner surface of the tube/channel passage, wire and helical coil inserts, corrugated tubes [6][7][8][9], outer grooved cylinder and inner rotating cylinder [10,11], helical and eccentric helical screw tape inserts [12][13][14], twisted tape inserts of different modifications [15][16][17][18][19][20][21][22][23][24][25], etc.…”

Section: Introductionmentioning

confidence: 99%

“…The exit mixer(13) was connected to the exit of the test section. It was fabricated from acetal and had an inner diameter of 19 mm, an outer diameter of 50 mm and a length of 200 mm.…”

mentioning

confidence: 99%

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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

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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.

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Section: Start and End Of The Transitional Flow Regimementioning

confidence: 99%

Section: Start and End Of The Transitional Flow Regimementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The exit mixer(13) was connected to the exit of the test section. It was fabricated from acetal and had an inner diameter of 19 mm, an outer diameter of 50 mm and a length of 200 mm.…”

mentioning

confidence: 99%

See 2 more Smart Citations

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

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“…This prompts the development of more compact and economic heat exchanger systems with lower operation cost. 3 Some of the commonly used turbulators, as reported in the research studies, [4][5][6][7] are wire brushes, coiled wires, longitudinal strip insert, helical screw tape insert and twisted tape inserts. Among these types of turbulators, twisted tape inserts have gained rising attention, due to their advantages of steady performance, simple configuration and ease of installation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation for Comparative Thermo-Hydraulic Performance of Turbulent Flow in Tubes with Twisted Tape Inserts

Mogaji

Idowu

Jen

2020

JES

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This article focused on investigating numerically the effects of key design parameters including tape thickness, tube wall to tape edge clearance and three different perforated shapes cut (circular, triangular and pentagon) on the heat transfer coefficient enhancement in tube with twisted tape inserts. Water was considered as the working fluid under the turbulent flow of Reynolds number (Re) between 12,000 and 22,000, with constant wall temperature of the tubes. It is found that due to the swirling flow and efficient mixing of the fluid, all the tape inserts considered in this study produced better thermalhydraulic performance than the plain tube without an insert. At the same time, tape inserts with small tube wall to tape edge clearance and considerable thickness value is beneficial to reduce the friction factor, consequently enhancing the heat transfer rate. Through the thermal performance factor (TPF) evaluation, the twisted tape with perforated triangular shape cut has an advantage over the pentagon and circular shapes cut with increasing Re. A maximum TPF as high as 1.68 can be obtained for the twisted tape with perforated triangular shape cut under low turbulent Re.

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Numerical evaluation of the heat transfer in a shell and corrugated coil tube heat exchanger with three various water‐based nanofluids

et al. 2021

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In this paper, turbulence heat transfer and nanofluid flow in a shell and corrugated coil tube heat exchanger are evaluated numerically. The three‐dimensional numerical simulations have been done by finite volume method using a commercial computational fluid dynamics code. The spatial discretization of mass, momentum, turbulence dissipation rate, and turbulence kinetic energy equations has been achieved by a second‐order upwind scheme. A SIMPLE algorithm has been used for velocity–pressure coupling. To calculate gradients, Green‐Gauss cell‐based method has been utilized. The cross‐section of the coil tube is lobe shaped. First, the impact of corrugated tube cross‐section type and then, the impact of utilizing different types of nanofluid on thermal performance are investigated. The outcomes indicate that at high Reynolds number, utilizing a five‐lobe cross‐section causes augmentation in Nusselt number and pressure drop by about 4.8% and 3.7%, respectively. However, the three‐lobe type shows the highest thermal performance. Moreover, water/CuO has the most thermal performance. As the volume concentration of the nanofluid increases, the thermal performance declines.

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Thermo-hydraulic analysis for a novel eccentric helical screw tape insert in a three dimensional tube

Cited by 53 publications

References 32 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

Numerical Simulation for Comparative Thermo-Hydraulic Performance of Turbulent Flow in Tubes with Twisted Tape Inserts

Numerical evaluation of the heat transfer in a shell and corrugated coil tube heat exchanger with three various water‐based nanofluids

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