MHD convection in a partially driven cavity with corner heating

Mondal, Milan K.; Biswas, Nirmalendu; Manna, Nirmal K.

doi:10.1007/s42452-019-1712-9

Cited by 24 publications

(21 citation statements)

References 30 publications

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“…Various types of complex problems (considering nanofluid/hybrid nanofluid, porous substances, magnetic fields, etc.) undergoing natural and mixed convection have been solved by the same code and several validations have been reported in our earlier works (Biswas et al, 2017;Mondal et al, 2019). However, using the reputed works (Sheremet and Pop, 2014;Nguyen et al, 2015), two new validation studies are conducted here to ensure the numerical accuracy of the present work.…”

Section: Numerical Methods and Validationmentioning

confidence: 99%

Magnetohydrodynamic mixed bioconvection of oxytactic microorganisms in a nanofluid-saturated porous cavity heated with a bell-shaped curved bottom

Biswas

Manna

Mandal³

et al. 2021

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Purpose This study aims to investigate thermo-bioconvection of oxytactic microorganisms occurring in a nanofluid-saturated porous lid-driven cavity in the presence of the magnetic field. The heating is provided through a bell-shaped curved bottom wall heated isothermally. The effects of the peak height of the curved bottom wall, bioconvection Rayleigh number (Rb), Darcy number (Da), Hartmann number (Ha), Peclet number (Pe), Lewis number (Le) and Grashof number (Gr) on the flow structure, temperature and the iso-concentrations of oxygen and microorganisms are examined and explained systematically. The local and global, characteristics of heat transfer and oxygen concentration, are estimated through the Nusselt number (Nu) and Sherwood number (Sh), respectively. Design/methodology/approach The governing equations of continuity, momentum, energy and additionally consisting of species transport equations for oxygen concentration and population density of microorganisms, are discretized by the finite volume method. The evolved linearized algebraic equations are solved iteratively through the alternate direction implicit scheme and the tri-diagonal matrix algorithm. The computation domain has meshed in non-uniform staggered grids. The entire computations are carried out through an in-house developed code written in FORTRAN following the SIMPLE algorithm. The third-order upwind and second-order central difference schemes are used for handling the advection and diffusion terms, respectively. The convergence criterion for the iterative process of achieving the final solution is set as 10–8 and 10–10, respectively, for the maximum residuals and the mass defect. Findings The results show that the flow and temperature distribution along with the iso-concentrations of oxygen and microorganisms are markedly affected by the curvature of the bottom wall. A secondary circulation is developed in the cavity that changes the flow physics significantly. The Nu increases with the peak height of the curved bottom wall and Da; however, it decreases with Ha and Rb. The Sh increases with Da but decreases with Ha and the peak height of the curved wall. Research limitations/implications A similar study of bioconvection could be extended further considering thermal radiation, chemical attraction, gravity, light, etc. Practical implications The outcomes of this investigation could be used in diverse fields of multi-physical applications such as in food industries, chemical processing equipment, fuel cell technology and enhanced oil recovery. Originality/value The insights of bioconvection of oxytactic microorganisms using a curved bottom surface along with other physical issues such as nanofluid, porous substance and magnetic field are addressed systematically and thoroughly.

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Section: Numerical Methods and Validationmentioning

confidence: 99%

Magnetohydrodynamic mixed bioconvection of oxytactic microorganisms in a nanofluid-saturated porous cavity heated with a bell-shaped curved bottom

Biswas

Manna

Mandal³

et al. 2021

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“…For solving the pressure correction, velocity, and temperature equations, the under-relaxation factors are taken as 1.0, 0.4, and 0.9, respectively. The code has been validated repeatedly and extensively in the context of earlier works [4,[37][38][39]. Biswas et al [4] have reported the code validation under mixed convective heat transfer through porous media packed in a lid-driven cavity.…”

Section: Code Validationmentioning

confidence: 99%

Energy-saving method of heat transfer enhancement during magneto-thermal convection in typical thermal cavities adopting aspiration

2020

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In the area of energy-efficient system development, the paper presents a novel approach aiming to enhance heat transfer during magnetohydrodynamic convection in thermal cavities by implementing a technique of free aspiration. Through two small openings, the proposed free aspiration naturally allows a partial admission of fresh fluid into the cavity (from its immediate surroundings) and eventually vents the admitted fluid out the cavity without any pumping device. The efficacy of aspiration technique, whether viable under different problem conditions, is worked out for various classical configurations like differential heating, corner heating, and split heating. The mathematical formulations are derived by applying the Maxwell model (for magnetic fields) and the Brinkman-Forchheimer-Darcy model (for porous media). The evolved complex and coupled mathematical equations (involving the laws of continuity, momentum, and energy) are solved by an indigenously developed computing code. The study is conducted exhaustively addressing both a porous domain and a clear domain in terms of pertinent design parameters-Hartmann number (Ha = 0-100), porosity (ε = 0.1-1), Darcy number (Da = 10 −7 -10 −3 ), Darcy-Rayleigh number (Ra m = 0.1-10 3 ), and Rayleigh number (Ra = 10 3 -10 6 ). The obtained results conclusively bring out an improved trend of heat transfer for all three thermal cavities due to the aspiration (without any pumping means). Even with the existence of flow-hindering porous substance and magnetic force, the augmentation in heat transfer could be as high as seven times more compared to their respective non-aspiration cases.

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“…The converged solutions are taken for the post-processing when the residuals and mass-defect fall below 10 À8 and 10 À10 , respectively. Earlier, this code with the appropriate validations (Biswas et al, 2015a;Biswas et al, 2015b;Biswas et al, 2016;Biswas et al, 2017;Biswas and Manna, 2018;Mondal et al, 2019) was used for simulating various flow situations undergoing natural or mixed convection. The capability of this code is continually enhanced to address newer flow physics.…”

Section: Numerical Aspectsmentioning

confidence: 99%

Thermo-bioconvection of oxytactic microorganisms in porous media in the presence of magnetic field

Biswas

Datta

Manna

et al. 2020

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Purpose This study aims to explore magnetohydrodynamic (MHD) thermo-bioconvection of oxytactic microorganisms in multi-physical directions addressing thermal gradient, lid motion, porous substance and magnetic field collectively using a typical differentially heated two-sided lid-driven cavity. The consequences of a range of pertinent parameters on the flow structure, temperature, oxygen isoconcentration and microorganisms’ isoconcentration are examined and explained in great detail. Design/methodology/approach Two-dimensional governing equations in a two-sided lid-driven porous cavity heated differentially and packed with oxytactic microorganisms under the influence of the magnetic field are solved numerically using the finite volume method-based computational fluid dynamics code. The evolved flow physics is analyzed assuming a steady laminar incompressible Newtonian flow within the validity of the Boussinesq approximation. The transport of oxytactic microorganisms is formulated by augmenting the continuum model. Findings The mechanisms involved with MHD-mixed thermo-bioconvection could have potential benefits for industrial exploitation. The distributions of fluid flow, temperature, oxygen and motile microorganisms are markedly modified with the change of convection regime. Both speed and direction of the translating walls significantly influence the concentration of the motile microorganisms. The concentration of oxygen and motile microorganisms is found to be higher at the upper portion of the cavity. The overall patterns of the fluid flow, temperature and the oxygen and microorganism distributions are markedly affected by the increase of magnetic field strength. Research limitations/implications The concept of the present study could be extended to other areas of bioconvection in the presence of gravity, light or chemical attraction. Practical implications The findings of the present study could be used to multi-physical applications like biomicrosystems, pollutant dispersion in aquifers, chemical catalytic converters, geothermal energy usage, petroleum oil reservoirs, enhanced oil recovery, fuel cells, thermal energy storage and others. Originality/value The MHD-mixed thermo-bioconvection of oxytactic microorganisms is investigated under different parametric conditions. The effect of pertinent parameters on the heat and mass transfers are examined using the Nusselt number and Sherwood number.

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MHD convection in a partially driven cavity with corner heating

Cited by 24 publications

References 30 publications

Magnetohydrodynamic mixed bioconvection of oxytactic microorganisms in a nanofluid-saturated porous cavity heated with a bell-shaped curved bottom

Magnetohydrodynamic mixed bioconvection of oxytactic microorganisms in a nanofluid-saturated porous cavity heated with a bell-shaped curved bottom

Energy-saving method of heat transfer enhancement during magneto-thermal convection in typical thermal cavities adopting aspiration

Thermo-bioconvection of oxytactic microorganisms in porous media in the presence of magnetic field

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