Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic
This study investigates the unsteady thermal convective transport mechanism of nanofluids(Water-Al2O3) with couple stress in a circular microchannel under the influence of electromagnetohydrodynamic(EMHD) and time-periodic pressure gradients. The Poisson–Boltzmann(PB) equation related to potential i...
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Elsevier
2025-05-01
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| Series: | Case Studies in Thermal Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X25002448 |
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| author | Jiali Zhang Guangpu Zhao Umer Farooq Jifeng Cui |
| author_facet | Jiali Zhang Guangpu Zhao Umer Farooq Jifeng Cui |
| author_sort | Jiali Zhang |
| collection | DOAJ |
| description | This study investigates the unsteady thermal convective transport mechanism of nanofluids(Water-Al2O3) with couple stress in a circular microchannel under the influence of electromagnetohydrodynamic(EMHD) and time-periodic pressure gradients. The Poisson–Boltzmann(PB) equation related to potential is derived using the Debye–Hückel approximation. The velocity and temperature distributions are obtained using the Green’s function method, and the Nusselt number and entropy generation are further derived. The effects of different dimensionless parameters are shown graphically and analyzed and discussed. The main results indicate that increasing the dimensionless couple stress parameters significantly increases the velocity, temperature, and convective heat transfer efficiency of the fluid. In addition, as the dimensionless frequency increased, the fluid flow rate decreased, energy transfer became more efficient, and thermal irreversibility and energy dissipation are notably reduced. It is also found that in nanofluids with low nanoparticle volume fractions, an increase in nanoparticle volume fraction enhanced the convective heat transfer capability of the fluid. The novelty of this study lies in providing a systematic theoretical analysis of the thermal convection mechanism of nanofluids with couple stress under complex flow conditions, especially under the effect of EMHD and time-periodic pressure gradients. This study not only offers a new perspective for understanding the thermal convective behavior of nanofluids under special flow conditions but also provides significant theoretical insights for the optimization design of microchannel heat exchangers and related devices, which can contribute to improving overall performance and optimizing fluid flow and heat transfer characteristics. |
| format | Article |
| id | doaj-art-e90837a181e2403aa76d28a50881abf7 |
| institution | OA Journals |
| issn | 2214-157X |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Case Studies in Thermal Engineering |
| spelling | doaj-art-e90837a181e2403aa76d28a50881abf72025-08-20T02:17:28ZengElsevierCase Studies in Thermal Engineering2214-157X2025-05-016910598410.1016/j.csite.2025.105984Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamicJiali Zhang0Guangpu Zhao1Umer Farooq2Jifeng Cui3College of Science, Inner Mongolia University of Technology, Hohhot, 010051, ChinaCollege of Science, Inner Mongolia University of Technology, Hohhot, 010051, ChinaSchool of Mathematical Sciences, Harbin Engineering University, Harbin, 150009, ChinaCollege of Science, Inner Mongolia University of Technology, Hohhot, 010051, China; Corresponding author.This study investigates the unsteady thermal convective transport mechanism of nanofluids(Water-Al2O3) with couple stress in a circular microchannel under the influence of electromagnetohydrodynamic(EMHD) and time-periodic pressure gradients. The Poisson–Boltzmann(PB) equation related to potential is derived using the Debye–Hückel approximation. The velocity and temperature distributions are obtained using the Green’s function method, and the Nusselt number and entropy generation are further derived. The effects of different dimensionless parameters are shown graphically and analyzed and discussed. The main results indicate that increasing the dimensionless couple stress parameters significantly increases the velocity, temperature, and convective heat transfer efficiency of the fluid. In addition, as the dimensionless frequency increased, the fluid flow rate decreased, energy transfer became more efficient, and thermal irreversibility and energy dissipation are notably reduced. It is also found that in nanofluids with low nanoparticle volume fractions, an increase in nanoparticle volume fraction enhanced the convective heat transfer capability of the fluid. The novelty of this study lies in providing a systematic theoretical analysis of the thermal convection mechanism of nanofluids with couple stress under complex flow conditions, especially under the effect of EMHD and time-periodic pressure gradients. This study not only offers a new perspective for understanding the thermal convective behavior of nanofluids under special flow conditions but also provides significant theoretical insights for the optimization design of microchannel heat exchangers and related devices, which can contribute to improving overall performance and optimizing fluid flow and heat transfer characteristics.http://www.sciencedirect.com/science/article/pii/S2214157X25002448Couple stressNanofluidsTime-periodic pressure gradientElectromagnetohydrodynamicEntropy generation |
| spellingShingle | Jiali Zhang Guangpu Zhao Umer Farooq Jifeng Cui Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic Case Studies in Thermal Engineering Couple stress Nanofluids Time-periodic pressure gradient Electromagnetohydrodynamic Entropy generation |
| title | Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic |
| title_full | Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic |
| title_fullStr | Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic |
| title_full_unstemmed | Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic |
| title_short | Unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time-periodic pressure gradient and electromagnetohydrodynamic |
| title_sort | unsteady thermal convective transport of nanofluids with couple stress through a circular microchannel under the time periodic pressure gradient and electromagnetohydrodynamic |
| topic | Couple stress Nanofluids Time-periodic pressure gradient Electromagnetohydrodynamic Entropy generation |
| url | http://www.sciencedirect.com/science/article/pii/S2214157X25002448 |
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