Numerical investigation of double-diffusive natural convection in a staggered cavity with two triangular obstacles

Al‐Farhany, Khaled; Alomari, Mohammed Azeez; Saleem, Khalid B.; Al‐Kouz, Wael; Biswas, Nirmalendu

doi:10.1140/epjp/s13360-021-01812-2

Cited by 30 publications

(8 citation statements)

References 48 publications

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“…It is assumed that there exists local thermal equilibrium (the same temperature for both porous structure and flowing fluid exists). The modeling of the porous structure is carried out using the Brinkman-Forchheimer-Darcy approach (Khanafer and Vafai, 2019; Manna et al , 2021b; Al-Farhany, 2021b). The induced magnetic Reynolds number is supposed to be negligible.…”

Section: Methodology and Mathematical Modelingmentioning

confidence: 99%

“…The Hall effect and Joule heating are also supposed to be insignificant (Maxwell, 1904) along with the negligible contributions of viscous dissipation and radiation effects (Nield and Bejan, 2013; Manna et al , 2021b). With the aforesaid assumptions, the dimensional and dimensionless transport equations are derived (Massoudi et al , 2020; Biswas et al , 2021f; Sarkar, 2021; Al-Farhany, 2021b; Biswas et al , 2021c) and given below.…”

Section: Methodology and Mathematical Modelingmentioning

confidence: 99%

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Hybrid nanofluid magnetohydrodynamic mixed convection in a novel W-shaped porous system

Mandal¹,

Biswas

Manna

et al. 2022

HFF

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Purpose This study aims to numerically examine the influence of various geometric parameters of a novel W-shaped porous cavity undergoing hybrid nanofluid-based magnetohydrodynamic mixed convection. The W-shaped cavity is modified from the classical trapezoidal cavity by constructing a triangular shape at its bottom. This cavity is isothermally active at the bottom, with different numbers and heights of the triangular peak (or undulation). The heated hybrid nanofluid (Cu–Al2O3–H2O) flow is cooled through the translating top wall. Inclined sidewalls are thermally insulated. To compare the impacts of change in geometric parameters, a square cavity under similar boundary conditions is also simulated. This study is carried out systematically addressing the various influences from a range of parameters like side angles (γ), number (m) and height (λ) of the bottom undulation, Reynolds number (Re), Richardson number (Ri), Darcy number (Da), Hartmann number (Ha), hybrid nanoparticles volume fraction (φ) on the overall thermal performance of the cavity. Design/methodology/approach Applying the finite volume approach, the transport equations involving multiphysical conditions like porous substance, hybrid nanofluid, magnetic field and shearing force are solved numerically by using a written FORTRAN-based code following the SIMPLE algorithm. The algebraic equations are solved over all the control volumes in an iterative process using the alternate direction implicit scheme and the tri-diagonal matrix algorithm. The converged solution of the iterative process is obtained when the relative error levels satisfy the convergence criterion of 10–8 and 10–10 for the maximum residuals and the mass defect, respectively. Findings It is revealed that an increase in the bottom undulation height always improves the thermal energy transfer despite the reduction of fluid volume. Thermal energy transfer significantly depends on the heating and cooling surface lengths, fluid volume in the cavity and the magnitude of the bottom undulation height of the W-shaped cavity. With the increase in bottom undulation height, effective heating length increases by ∼28%, which leads to a ∼15% reduction in the effective volume of the working fluid and a gain in heat transfer by ∼56.48%. In general, the overall thermal energy transport is improved by increasing Re, Ri and Da; whereas it is suppressed by increasing Ha. Research limitations/implications There are many opportunities for future research experimentally or numerically, considering different curvature effects, orientations of the geometry, working fluids, boundary conditions, etc. Furthermore, this study could be extended by considering unsteady flow or turbulent flow. Practical implications In many modern systems/processes pertaining to materials processing, continuous casting, food processing, chemical reactors, biomedical applications, etc. fine control in the transport process is a major concern. The findings of this analysis can effectively be useful for other applications for getting more control features in terms of achieving the operational objectives. The approach of the system analysis (considering geometrical size parameters to delve into the underlying transport physics) and the obtained simulated results presented in the work can usefully be applicable to similar thermal systems/devices such as materials processing, thermal mixing, chemical reactors, heat exchangers, etc. Originality/value From the well-documented and vast pool of literature survey, it is understood that there exists no such investigation on the considered geometry and study. This study contributes a lot to understanding magnetic field moderated thermofluid flow of a hybrid nanofluid in a porous medium filled W-shaped cavity, in consideration of different geometrical shape parameters (undulation peak numbers at bottom wall, peak heights, side angles and heating and cooling length). Findings brought by this study provide great insights into the design and operation under various ranges of multiphysical thermofluid-flow processing phenomena.

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Section: Methodology and Mathematical Modelingmentioning

confidence: 99%

Section: Methodology and Mathematical Modelingmentioning

confidence: 99%

Hybrid nanofluid magnetohydrodynamic mixed convection in a novel W-shaped porous system

Mandal¹,

Biswas

Manna

et al. 2022

HFF

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“…They noted that average Nusselt number and Sherwood number are elevated with increasing Rayleigh number, heat generation parameter, Lewis number and solid volume fraction. Al-Farhany et al [37] investigate double-diffusive natural convection in a complex enclosure containing two equilateral triangular obstacles. Ali Doostali and Marzieh Rezazadeh [38] used the lattice Boltzmann method to investigate the natural convection heat transfer in a cavity with three heaters are situated at the bottom wall.…”

Section: Nomenclaturementioning

confidence: 99%

Numerical simulation of thermal management during natural convection in a porous triangular cavity containing air and hot obstacles

chandanam

Lakshmi

Venkatadri³

et al. 2021

Eur. Phys. J. Plus

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A numerical study is presented of laminar viscous magnetohydrodynamic natural convection flow in a triangular shaped porous enclosure filled with electrically conducting air and containing two hot obstacles. The mathematical model is formulated in terms of dimensional partial differential equations. The pressure gradient term is eliminated by using the vorticitystream ( − ) function approach. The emerging dimensionless governing equations are employed by the regular finite difference scheme along with thermofluidic boundary conditions. The efficiency of the obtained computed results for isotherms and streamlines are validated via comparison with previously published work. The impact of physical parameters on streamlines and temperature contours for an extensive range of Rayleigh number (Ra=10 3 -10 5 ), Hartmann magnetohydrodynamic number (Ha=5-30), Darcy parameter (Da=0.0001-0.1) for fixed Prandtl number (Pr = 0.71) are considered. Numerical results are also presented for local and average Nusselt numbers along the hot base wall. Interesting features of the thermofluid behaviour are revealed. At lower Rayleigh number the isotherms are generally parallel to the inclined wall and only distorted substantially near the obstacles at the left vertical adiabatic wall; however, with increasing Rayleigh number, this distortion is magnified in the core zone and simultaneously warmer zones expand towards the inclined cold wall. The simulations are relevant to magnetic materials processing and hybrid magnetic fuel cells.

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“…The data showed that increasing the Darcy number directly with the modified Rayleigh number and fin dimension increased the average Nusselt number. They also reviewed current research for natural convection in cavities of different shapes with internal hosts, such as the MHD effect and double diffusion [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ].…”

Section: Introductionmentioning

confidence: 99%

The Baffle Length Effects on the Natural Convection in Nanofluid-Filled Square Enclosure with Sinusoidal Temperature

et al. 2022

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The proper process of applying heat to many technological devices is a significant challenge. There are many nanofluids of different sizes used inside the system. The current study combines this potential to improve convection effects, considering numerical simulations of natural convection using Cu/water nanofluids in a square enclosure with bottom blocks embedded in baffles. The enclosure consists of two vertical walls with isothermal boundary conditions; the left wall is the sinusoidal heat source, whereas the right wall is cooled. The investigations dealt with the influences of nanoparticle concentration, Rayleigh number, baffle length, and thermal conductivity ratioon isotherms, stream functions, and average Nusselt number. The results present that, when the Rayleigh number rises, the fluid flow velocity increases, and the heat transfer improves. Furthermore, the baffle length case (Lb = 0.3) provides higher heat transfer characteristics than other baffle height cases.

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Numerical investigation of double-diffusive natural convection in a staggered cavity with two triangular obstacles

Cited by 30 publications

References 48 publications

Hybrid nanofluid magnetohydrodynamic mixed convection in a novel W-shaped porous system

Hybrid nanofluid magnetohydrodynamic mixed convection in a novel W-shaped porous system

Numerical simulation of thermal management during natural convection in a porous triangular cavity containing air and hot obstacles

The Baffle Length Effects on the Natural Convection in Nanofluid-Filled Square Enclosure with Sinusoidal Temperature

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