Numerical investigation of several twisted tubes with non-conventional tube cross sections on heat transfer and pressure drop

B. Indurain; D. Uystepruyst; F. Beaubert; S. Lalot

doi:10.1007/s10973-019-08965-4

Numerical investigation of several twisted tubes with non-conventional tube cross sections on heat transfer and pressure drop

B. Indurain^*, D. Uystepruyst, F. Beaubert, S. Lalot, Helgadóttir

^*Corresponding author for this work

Faculty of Industrial Engineering, Mechanical Engineering and Computer Science

Research output: Contribution to journal › Article › peer-review

6 Citations (Scopus)

Abstract

Numerical simulations were performed with the open-source CFD software OpenFOAM to investigate the ability of several configurations of short-length twisted tube geometries with non-circular cross section connected to tubes with circular cross section to induce a swirling flow. The heat transfer and the pressure drop linked to the generated swirling flow are also calculated. The swirling flow is modeled using a k-ω SST turbulence model with a low-Reynolds approach. It is shown that a short-length twisted tube with an elliptical cross section (STE) is able to generate a swirling flow, but its intensity greatly depends on its twist pitch and its aspect ratio. The lower the aspect ratio, the higher the swirl intensity. For a Reynolds number ranging from 10,000 to 100,000, the results reveal that compared to a plain tube, the STE with the lowest aspect ratio achieves enhancing the heat transfer from 22 to 90% at the cost of an increased pressure drop of, respectively, 63 and 129%. The second part of the study is focused on a short-length twisted tube with a three-lobed cross section, and the results reveal that the generated swirling flow is even more intense than with the STE and that the heat transfer enhancement goes from 30 to 105% at the cost of an increased pressure drop from 137 to 180%.

Original language	English
Pages (from-to)	1555-1568
Number of pages	14
Journal	Journal of Thermal Analysis and Calorimetry
Volume	140
Issue number	3
DOIs	https://doi.org/10.1007/s10973-019-08965-4
Publication status	Published - 1 May 2020

Bibliographical note

Funding Information:
The authors would like to thank the financial support of the Association Nationale Recherche Technologie (ANRT) through the CIFRE Grant No. 2017/1437. a Major axis of the ellipse, m A Wetted area, m 2 b Minor axis of the ellipse, m c Aspect ratio of the ellipse, dimensionless c p Specific heat capacity, J kg −1 K −1 C f Skin friction coefficient, dimensionless Δ p Pressure drop, Pa D h Hydraulic diameter, m e Quantity to evaluate for the GCI f Friction factor coefficient, dimensionless GCI Grid convergence index h Heat transfer coefficient, W m −2 K −1 I Turbulence intensity, dimensionless k Turbulent kinetic energy, J kg −1 l Turbulent mixing length, m L Total length of the tested tube, m m Mass flow rate, kg s −1 Nu Nusselt number, dimensionless P Twist pitch, m r Refinement ratio, dimensionless Re Reynolds number, dimensionless S Swirl number, dimensionless T Temperature, K U Fluid velocity, m s −1 Q Heat flux, W z Axial position, m z * Dimensionless axial position (z D h −1 ) z 1 * Downstream dimensionless axial position z * = 24 α Order of accuracy for the GCI, dimensionless λ Thermal conductivity, W m −1 K −1 μ Dynamic viscosity, Pa.s ρ Fluid density, kg m −3 τ w Wall shear stress, Pa ω Turbulent kinetic energy dissipation rate, s −1

Publisher Copyright:
© 2019, Akadémiai Kiadó, Budapest, Hungary.

Other keywords

CFD
Decaying swirling flow
Elliptical
Heat transfer
Three-lobed
Twisted tubes

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10.1007/s10973-019-08965-4

Cite this

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title = "Numerical investigation of several twisted tubes with non-conventional tube cross sections on heat transfer and pressure drop",

abstract = "Numerical simulations were performed with the open-source CFD software OpenFOAM to investigate the ability of several configurations of short-length twisted tube geometries with non-circular cross section connected to tubes with circular cross section to induce a swirling flow. The heat transfer and the pressure drop linked to the generated swirling flow are also calculated. The swirling flow is modeled using a k-ω SST turbulence model with a low-Reynolds approach. It is shown that a short-length twisted tube with an elliptical cross section (STE) is able to generate a swirling flow, but its intensity greatly depends on its twist pitch and its aspect ratio. The lower the aspect ratio, the higher the swirl intensity. For a Reynolds number ranging from 10,000 to 100,000, the results reveal that compared to a plain tube, the STE with the lowest aspect ratio achieves enhancing the heat transfer from 22 to 90% at the cost of an increased pressure drop of, respectively, 63 and 129%. The second part of the study is focused on a short-length twisted tube with a three-lobed cross section, and the results reveal that the generated swirling flow is even more intense than with the STE and that the heat transfer enhancement goes from 30 to 105% at the cost of an increased pressure drop from 137 to 180%.",

keywords = "CFD, Decaying swirling flow, Elliptical, Heat transfer, Three-lobed, Twisted tubes",

author = "B. Indurain and D. Uystepruyst and F. Beaubert and S. Lalot and Helgad{\'o}ttir",

note = "Funding Information: The authors would like to thank the financial support of the Association Nationale Recherche Technologie (ANRT) through the CIFRE Grant No. 2017/1437. a Major axis of the ellipse, m A Wetted area, m 2 b Minor axis of the ellipse, m c Aspect ratio of the ellipse, dimensionless c p Specific heat capacity, J kg −1 K −1 C f Skin friction coefficient, dimensionless Δ p Pressure drop, Pa D h Hydraulic diameter, m e Quantity to evaluate for the GCI f Friction factor coefficient, dimensionless GCI Grid convergence index h Heat transfer coefficient, W m −2 K −1 I Turbulence intensity, dimensionless k Turbulent kinetic energy, J kg −1 l Turbulent mixing length, m L Total length of the tested tube, m m Mass flow rate, kg s −1 Nu Nusselt number, dimensionless P Twist pitch, m r Refinement ratio, dimensionless Re Reynolds number, dimensionless S Swirl number, dimensionless T Temperature, K U Fluid velocity, m s −1 Q Heat flux, W z Axial position, m z * Dimensionless axial position (z D h −1 ) z 1 * Downstream dimensionless axial position z * = 24 α Order of accuracy for the GCI, dimensionless λ Thermal conductivity, W m −1 K −1 μ Dynamic viscosity, Pa.s ρ Fluid density, kg m −3 τ w Wall shear stress, Pa ω Turbulent kinetic energy dissipation rate, s −1 Publisher Copyright: {\textcopyright} 2019, Akad{\'e}miai Kiad{\'o}, Budapest, Hungary.",

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doi = "10.1007/s10973-019-08965-4",

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AU - Indurain, B.

AU - Uystepruyst, D.

AU - Beaubert, F.

AU - Lalot, S.

AU - Helgadóttir,

N1 - Funding Information: The authors would like to thank the financial support of the Association Nationale Recherche Technologie (ANRT) through the CIFRE Grant No. 2017/1437. a Major axis of the ellipse, m A Wetted area, m 2 b Minor axis of the ellipse, m c Aspect ratio of the ellipse, dimensionless c p Specific heat capacity, J kg −1 K −1 C f Skin friction coefficient, dimensionless Δ p Pressure drop, Pa D h Hydraulic diameter, m e Quantity to evaluate for the GCI f Friction factor coefficient, dimensionless GCI Grid convergence index h Heat transfer coefficient, W m −2 K −1 I Turbulence intensity, dimensionless k Turbulent kinetic energy, J kg −1 l Turbulent mixing length, m L Total length of the tested tube, m m Mass flow rate, kg s −1 Nu Nusselt number, dimensionless P Twist pitch, m r Refinement ratio, dimensionless Re Reynolds number, dimensionless S Swirl number, dimensionless T Temperature, K U Fluid velocity, m s −1 Q Heat flux, W z Axial position, m z * Dimensionless axial position (z D h −1 ) z 1 * Downstream dimensionless axial position z * = 24 α Order of accuracy for the GCI, dimensionless λ Thermal conductivity, W m −1 K −1 μ Dynamic viscosity, Pa.s ρ Fluid density, kg m −3 τ w Wall shear stress, Pa ω Turbulent kinetic energy dissipation rate, s −1 Publisher Copyright: © 2019, Akadémiai Kiadó, Budapest, Hungary.

PY - 2020/5/1

Y1 - 2020/5/1

N2 - Numerical simulations were performed with the open-source CFD software OpenFOAM to investigate the ability of several configurations of short-length twisted tube geometries with non-circular cross section connected to tubes with circular cross section to induce a swirling flow. The heat transfer and the pressure drop linked to the generated swirling flow are also calculated. The swirling flow is modeled using a k-ω SST turbulence model with a low-Reynolds approach. It is shown that a short-length twisted tube with an elliptical cross section (STE) is able to generate a swirling flow, but its intensity greatly depends on its twist pitch and its aspect ratio. The lower the aspect ratio, the higher the swirl intensity. For a Reynolds number ranging from 10,000 to 100,000, the results reveal that compared to a plain tube, the STE with the lowest aspect ratio achieves enhancing the heat transfer from 22 to 90% at the cost of an increased pressure drop of, respectively, 63 and 129%. The second part of the study is focused on a short-length twisted tube with a three-lobed cross section, and the results reveal that the generated swirling flow is even more intense than with the STE and that the heat transfer enhancement goes from 30 to 105% at the cost of an increased pressure drop from 137 to 180%.

AB - Numerical simulations were performed with the open-source CFD software OpenFOAM to investigate the ability of several configurations of short-length twisted tube geometries with non-circular cross section connected to tubes with circular cross section to induce a swirling flow. The heat transfer and the pressure drop linked to the generated swirling flow are also calculated. The swirling flow is modeled using a k-ω SST turbulence model with a low-Reynolds approach. It is shown that a short-length twisted tube with an elliptical cross section (STE) is able to generate a swirling flow, but its intensity greatly depends on its twist pitch and its aspect ratio. The lower the aspect ratio, the higher the swirl intensity. For a Reynolds number ranging from 10,000 to 100,000, the results reveal that compared to a plain tube, the STE with the lowest aspect ratio achieves enhancing the heat transfer from 22 to 90% at the cost of an increased pressure drop of, respectively, 63 and 129%. The second part of the study is focused on a short-length twisted tube with a three-lobed cross section, and the results reveal that the generated swirling flow is even more intense than with the STE and that the heat transfer enhancement goes from 30 to 105% at the cost of an increased pressure drop from 137 to 180%.

KW - CFD

KW - Decaying swirling flow

KW - Elliptical

KW - Heat transfer

KW - Three-lobed

KW - Twisted tubes

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Numerical investigation of several twisted tubes with non-conventional tube cross sections on heat transfer and pressure drop

Abstract

Bibliographical note

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