Numerical study of forced convection in a 3D flow of a non‐Newtonian fluid through a porous duct

Nebbali, Rachid; Bouhadef, Khedidja

doi:10.1108/09615530610702041

Cited by 10 publications

(8 citation statements)

References 21 publications

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“…The initial azimuthal velocity of the inner cylinder is set to 0.15, the mesh size to 20 × 76, and the radius ratio to 0.5. For the non-Newtonian fluid flows the exponent n was chosen in the range between 0.5 and 1.5 while the Reynolds number was varied from 20 to 150 [35][36][37][38][39][40][41][42][43][44][45][46][47][48]. 053002-9 Figure 4 illustrates the dimensionless azimuthal velocity along the radial position for different values of the power-law index n. It is shown that the velocity profile decays gradually along the radial position for the considered fluids.…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

Numerical investigation of non-Newtonian fluids in annular ducts with finite aspect ratio using lattice Boltzmann method

Khali

Nebbali²,

De³

et al. 2013

Phys. Rev. E

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In this work the instability of the Taylor-Couette flow for Newtonian and non-Newtonian fluids (dilatant and pseudoplastic fluids) is investigated for cases of finite aspect ratios. The study is conducted numerically using the lattice Boltzmann method (LBM). In many industrial applications, the apparatuses and installations drift away from the idealized case of an annulus of infinite length, and thus the end caps effect can no longer be ignored. The inner cylinder is rotating while the outer one and the end walls are maintained at rest. The lattice two-dimensional nine-velocity (D2Q9) Boltzmann model developed from the Bhatnagar-Gross-Krook approximation is used to obtain the flow field for fluids obeying the power-law model. The combined effects of the Reynolds number, the radius ratio, and the power-law index n on the flow characteristics are analyzed for an annular space of finite aspect ratio. Two flow modes are obtained: a primary Couette flow (CF) mode and a secondary Taylor vortex flow (TVF) mode. The flow structures so obtained are different from one mode to another. The critical Reynolds number Re(c) for the passage from the primary to the secondary mode exhibits the lowest value for the pseudoplastic fluids and the highest value for the dilatant fluids. The findings are useful for studies of the swirling flow of non-Newtonians fluids in axisymmetric geometries using LBM. The flow changes from the CF to TVF and its structure switches from the two-cells to four-cells regime for both Newtonian and dilatant fluids. Contrariwise for pseudoplastic fluids, the flow exhibits 2-4-2 structure passing from two-cells to four cells and switches again to the two-cells configuration. Furthermore, the critical Reynolds number presents a monotonic increase with the power-law index n of the non-Newtonian fluid, and as the radius ratio grows, the transition flow regimes tend to appear for higher critical Reynolds numbers.

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Section: Numerical Results and Discussionmentioning

confidence: 99%

Numerical investigation of non-Newtonian fluids in annular ducts with finite aspect ratio using lattice Boltzmann method

Khali

Nebbali²,

De³

et al. 2013

Phys. Rev. E

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“…SiC) [26]. Adopting the 2D Brinkman extension of the classical Darcy equation under steady-state conditions; the conservation equations which describe the transport phenomenon of the viscoplastic fluid within the porous square can be summarized as follows [17,[27][28][29][30]:…”

Section: Problem Statement and Mathematical Formulationmentioning

confidence: 99%

Circular heat and solute source within a viscoplastic porous enclosure: The critical source dimension for optimum transfers

Ragui¹,

Boutra²,

Benkahla³

et al. 2018

IJHT

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Through our paper, thermosolutal convection of viscoplastic materials 'so called Bingham plastics' which occurs into a porous matrix with an inner pollutant source has been treated numerically, in the aim to light out the impact of some relevant parameters; such Lewis and porous Rayleigh numbers; as well as the buoyancy ratio and the source dimension one; on a such conjugate phenomenon. To do so, the physical model for the momentum conservation equations is made using the Brinkman extension of the classical Darcy equation. The set of coupled equations is solved using the finite volume method and the SIMPLER algorithm. The heat and solute source within the porous space has taken a circular shape. Simply said, our pollutant source is a transport pipe which presented in 2D.To handle the latter in Cartesian Coordinates; the Cartesian Cut-Cell approach was adopted. After a careful treatment of such double-diffusive convection within the Bingham-porous space; powerful expressions that expect the mean transfer rates in such industrial geometry are set forth as a function of the governing parameters. These correlations, which predicted with ±3% the numerical results, may count as a complement to previous Newtonian-fluid researches. It is to note that the validity of the computing code was ascertained by comparing our results with experimental data and numerical ones, already available in the literature.

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“…The techniques used in reality for the purpose of transfer of heat are classified into two, namely active and passive methods (Mereu et al, 2013;Rashidi et al, 2020). The uses of corrugation in the wall (Mehta and Pati, 2018;Mousavi et al, 2020;Jaferian et al, 2019;Tiwari et al, 2017;Moharana, 2019b, 2019c), twisted tapes, ribs, baffles (Boruah et al, 2018;Boruah et al, 2019a) metallic porous media (Shamsabadi et al, 2019;Nebbali and Bouhadef, 2006;Bhowmick et al, 2020) and nanofluid (Rashidi et al, 2019;Boruah et al, 2019b;Darbari et al, 2020) are some of the passive heat transfer techniques for which external energy other than the pumping power is not needed. While the active techniques need external energy other than the pumping power to alter the flow field, and hence the heat transfer rate such as the application of electrical and magnetic fields (Rashid and Liang, 2020;Wang et al, 2019) for the flow of electrically conductive fluid.…”

Section: Introductionmentioning

confidence: 99%

Thermo-hydraulic and entropy generation analysis for magnetohydrodynamic pressure driven flow of nanofluid through an asymmetric wavy channel

Mehta

Pati

2020

HFF

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Purpose The purpose of this paper is to analyze the thermal, hydraulic and entropy generation characteristics for the magneto-hydrodynamic (MHD) pressure-driven flow of Al2O3-water nanofluid through an asymmetric wavy channel. Design/methodology/approach Galerkin finite element method is used to solve the governing transport equations numerically within the computational domain using the appropriate boundary conditions. The temperature and flow fields are computed by varying Reynolds number (Re), Hartmann number (Ha) and nano-particle volume fraction (ϕ) in the following range: 10 ≤ Re ≤ 500, 0 ≤ Ha ≤ 75 and 0 ≤ ϕ ≤ 5%. Findings The formation of the recirculation zones in the wavy passages, the size of it and the strength of the vortices formed can be modulated by the application of the magnetic field. The overall heat transfer rate increases with Ha for all ϕ both for a lower and higher regime of Re although the enhancement is more for lower values of Re and nanofluids as compared to base fluid and for intermediate values of Re, the effect of a magnetic field is almost insignificant. The magnetic performance factor (PFmagnetic) decreases with Ha although the rate of decrement varies with Re. The increase ϕ also enhances PFmagnetic especially at lower and higher values of Re. The addition of nano-particle enhances the entropy generation at lower values of the Re, while the opposite effect is seen for higher values of Re. Practical implications The present study has enormous practical relevance for the design of heat exchanger applied for solar collectors, process plants, textile and aerospace applications. Originality/value The combined effects on the heat transfer rate and the associated pressure drop penalty due to the applied magnetic field for the flow of nanofluid through an asymmetric wavy channel have not been reported to date. The effect of the magnetic field on the formation of recirculation zones and hot spot intensity in the asymmetric wavy channel has been examined in detail. The PFmagnetic is investigated first time for the MHD nanofluid flow through a wavy channel.

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Numerical study of forced convection in a 3D flow of a non‐Newtonian fluid through a porous duct

Cited by 10 publications

References 21 publications

Numerical investigation of non-Newtonian fluids in annular ducts with finite aspect ratio using lattice Boltzmann method

Numerical investigation of non-Newtonian fluids in annular ducts with finite aspect ratio using lattice Boltzmann method

Circular heat and solute source within a viscoplastic porous enclosure: The critical source dimension for optimum transfers

Thermo-hydraulic and entropy generation analysis for magnetohydrodynamic pressure driven flow of nanofluid through an asymmetric wavy channel

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