Hydrodynamic analysis of nanofluid’s convective heat transfer in channels with extended surfaces

Soleimani, Rasa; Zargartalebi, Mohammad; Azaiez, Jalel; Gates, Ian D.

doi:10.1063/5.0036621

Cited by 16 publications

(5 citation statements)

References 72 publications

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“…LBM is a discrete form of the continuous kinetic Boltzmann equation with discretised time and space coordinates 35 . The solution algorithm assumes the fluid as a large number of randomly moving fictive particles that exchange momentum (and energy for the non-isothermal problems) through collision and streaming processes, evolving the density of the fluid 𝜌(𝑥 , 𝑡), for 𝑥 the position and 𝑡 the time 51 . A finite set of vectors are used to limit the space coordinate and construct a lattice to denote the directions where the fluid particles can move.…”

Section: Governing Equationsmentioning

confidence: 99%

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On the effect of flow regime and pore structure on the flow signatures in porous media

Farahani

Nezhad

2022

Physics of Fluids

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In this study, lattice Boltzmann method (LBM) is utilised for three-dimensional simulation of fluid flow through two porous structures, consisting of grains with the same diameter: (i) a homogeneous porous domain, in which the grains are placed with a simple cubic packing configuration, and (ii) a randomly-packed porous domain. An ultra-fine mesh size is considered to perform the simulations in three orders of magnitude of Reynolds number (), covering laminar to turbulent flow regimes, and capture different flow signatures. Pore velocity fields are derived, and their sample probability density functions (PDF) are analyzed versus time to investigate the dynamics of the flow. The analysis of the PDFs clearly shows that stagnant zones play a significant role in the formation of the pore flow fields, manifested by multimodal PDFs, and the distribution of the velocities in porous media at various cannot be characterized by a single PDF model regardless of the pore structure. While the velocities at the stagnant regions and in the vicinity of the solid boundaries are primarily affected by the viscous forces and exhibit a power-law PDF at different , the velocities in the main (preferential) flow pathways away from the boundaries are shown to be influenced by the inertial forces, hence having an exponential PDF when is low. At high, however, depending on the tortuosity of the porous structure, the velocities may exhibit an exponential or even Laplace PDF.

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Section: Governing Equationsmentioning

confidence: 99%

“…Fluid flow through a cylindrical tube driven by a pressure gradient known as Poiseuille flow is extensively used as a benchmark to verify the accuracy and convergence of various CFD methods 51,52 . The exact analytical solution for Poiseuille flow in a cylindrical coordinate can be expressed as 80 :…”

Section: Supplementary Materialsmentioning

confidence: 99%

On the effect of flow regime and pore structure on the flow signatures in porous media

Farahani

Nezhad

2022

Physics of Fluids

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“…The applications of the pore-scale approach with LBM can be dated back to 1989 when Succi et al [16] studied a random porous medium using this method. Soleimani et al [17] studied heat transfer in channels with extended surfaces and nanoparticles using LBM. They utilized a two-distribution functions model that accounts for the non-homogeneous nanoparticle distribution and compared it with a single-distribution function model that assumes a uniform nanoparticle distribution.…”

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann Modelling of Fluid Flow through Porous Media: A Comparison between Pore-Structure and Representative Elementary Volume Methods

2023

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In this study, we present a novel comparison between pore-structure (PS) and representative elementary volume (REV) methods for modelling fluid flow through porous media using a second-order lattice Boltzmann method (LBM). We employ the LBM to demonstrate the importance of the configuration of square obstacles in the PS method and compare the PS and the REV methods. This research provides new insights into fluid flow through porous media as a novel study. The behaviour of fluid flow through porous media has important applications in various engineering structures. The aim of this study is to compare two methods for simulating porous media: the PS method, which resolves the details of the solid matrix, and the REV method, which treats the porous medium as a continuum. Our research methodology involves using different arrangements of square obstacles in a channel including in-line, staggered and random for the PS method and a porosity factor and permeability value for the REV method. We found that the porosity and obstacle arrangement have significant effects on the pressure drop, permeability and flow patterns in the porous region. While the REV method cannot simulate the details of fluid flow through pore structures compared to the PS method, it is able to provide a better understanding of the flow field details around obstacles (Tortuosity). This study has important applications in improving our understanding of transport phenomena in porous media. Our results can be useful for designing and optimizing various engineering systems involving porous media.

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“…Meanwhile, the passive enhancement methods do not need the presence of external power to strengthen heat transfer rate. Some applications of passive methods are given as: coiled tubes (Salimpour, 2008), rough surfaces (Aupoix, 2015), extended surfaces (Soleimani et al , 2021), swirl flow devices and additives for fluids (Lo et al , 2005). Besides, the rate of heat transfer through various other mechanisms can be improved.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of flow and thermal characteristics of aluminum block exchanger using surface-modified and recycled nanofluids

Gülmüş

Muratçobanoğlu

Mandev

et al. 2023

HFF

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Purpose The purpose of this study is to numerically and experimentally survey the thermal efficiency of a block-type heat exchanger operated in different working conditions by using pure water and two nanofluids as heat transfer fluids. Design/methodology/approach An aluminum block-type heat exchanger integrated with Peltier thermoelectric element was designed and installed to operate in a cycle, and the thermal performance of the heat exchanger, heat transfer rate, Nusselt and heat transfer coefficient variations were examined at different bath water temperatures by using recycled nanofluids. New generation surface-modified Fe3O4@SiO2-mix-(CH2)3Cl@Imidazol/water nanofluid was used as heat transfer fluid in the cycle. In addition, CFD simulation was performed using ANSYS/Fluent to investigate the temperature distribution and fluid flow structure in the used heat exchanger. Findings Experiments were carried out by using numerical and experimental methods. In the experiments, the operating conditions such as flow rate, volume fraction of the nanofluid and water bath temperature were changed to find the effect of each parameter on the thermal efficiency. The Reynolds number varied depending on the test conditions, which was calculated in the range of approximately 100 < Re < 350. In addition, Nusselt number and heat transfer coefficient of test fluids were very close to each other. For 0.4% nanofluid, the maximum h value was obtained as 3837.1, when the Reynolds number was measured as 314.4. Originality/value In the scientific articles published in the field of heat exchangers operated by nanofluids, little attention has been paid to the stability of the nanofluids and sedimentation of particles in the base fluids. In addition, in most cases, experiments were implemented using an electrical resistance as a heat source. In this research, stable surface-modified nanofluids were used as heat transfer fluids, and it was found that the Peltier thermoelectric can be used as heat sources with acceptable efficiency in flat-type heat exchangers and even non-circular channels.

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Hydrodynamic analysis of nanofluid’s convective heat transfer in channels with extended surfaces

Cited by 16 publications

References 72 publications

On the effect of flow regime and pore structure on the flow signatures in porous media

On the effect of flow regime and pore structure on the flow signatures in porous media

Lattice Boltzmann Modelling of Fluid Flow through Porous Media: A Comparison between Pore-Structure and Representative Elementary Volume Methods

Experimental and numerical investigation of flow and thermal characteristics of aluminum block exchanger using surface-modified and recycled nanofluids

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