Unsteady squeezing flow of Cu-Al2O3/water hybrid nanofluid in a horizontal channel with magnetic field

AbstractThe proficiency of hybrid nanofluid from Cu-Al2O3/water formation as the heat transfer coolant is numerically analyzed using the powerful and user-friendly interface bvp4c in the Matlab software. For that purpose, the Cu-Al2O3/water nanofluid flow between two parallel plates is examined where the lower plate can be deformed while the upper plate moves towards/away from the lower plate. Other considerable factors are the wall mass suction/injection and the magnetic field that applied on the lower plate. The reduced ordinary (similarity) differential equations are solved using the bvp4c application. The validation of this novel model is conducted by comparing a few of numerical values for the reduced case of viscous fluid. The results imply the potency of this heat transfer fluid which can enhance the heat transfer performance for both upper and lower plates approximately by 7.10% and 4.11%, respectively. An increase of squeezing parameter deteriorates the heat transfer coefficient by 4.28% (upper) and 5.35% (lower), accordingly. The rise of suction strength inflates the heat transfer at the lower plate while the presence of the magnetic field shows a reverse result.

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Effect of Magnetic Field on the Forced Convective Heat Transfer of Water–Ethylene Glycol-Based Fe3O4 and Fe3O4–MWCNT Nanofluids

Applied Sciences ◽

10.3390/app11104683 ◽

2021 ◽

Vol 11 (10) ◽

pp. 4683

Author(s):

Areum Lee ◽

Chinnasamy Veerakumar ◽

Honghyun Cho

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Heat Transfer Coefficient ◽

Field Strength ◽

Ethylene Glycol ◽

Convective Heat Transfer ◽

Convective Heat ◽

Hybrid Nanofluid ◽

Forced Convective Heat Transfer ◽

The Magnetic Field

This paper discusses the forced convective heat transfer characteristics of water–ethylene glycol (EG)-based Fe3O4 nanofluid and Fe3O4–MWCNT hybrid nanofluid under the effect of a magnetic field. The results indicated that the convective heat transfer coefficient of magnetic nanofluids increased with an increase in the strength of the magnetic field. When the magnetic field strength was varied from 0 to 750 G, the maximum convective heat transfer coefficients were observed for the 0.2 wt% Fe3O4 and 0.1 wt% Fe3O4–MWNCT nanofluids, and the improvements were approximately 2.78% and 3.23%, respectively. The average pressure drops for 0.2 wt% Fe3O4 and 0.2 wt% Fe3O4–MWNCT nanofluids increased by about 4.73% and 5.23%, respectively. Owing to the extensive aggregation of nanoparticles by the external magnetic field, the heat transfer coefficient of the 0.1 wt% Fe3O4–MWNCT hybrid nanofluid was 5% higher than that of the 0.2 wt% Fe3O4 nanofluid. Therefore, the convective heat transfer can be enhanced by the dispersion stability of the nanoparticles and optimization of the magnetic field strength.

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Effect of Magnetic Field on the Laminar Heat Transfer Performance of Hybrid Nanofluid in a Lid Driven Cavity Over Solid Block

ASME 2020 Power Conference ◽

10.1115/power2020-16696 ◽

2020 ◽

Author(s):

Rajesh Nimmagadda ◽

Durga Prakash Matta ◽

Rony Reuven ◽

Lazarus Godson Asirvatham ◽

Somchai Wongwises ◽

...

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Uniform Magnetic Field ◽

Conjugate Heat Transfer ◽

Heat Transfer Performance ◽

Hybrid Nanofluid ◽

Transfer Performance ◽

Driven Cavity ◽

The Magnetic Field ◽

Solid Block

Abstract A 2D numerical investigation has been carried out to obtain the heat transfer performance of hybrid (Al2O3 + Ag) nanofluid in a lid driven cavity over solid block under the influence of uniform as well as non-uniform magnetic field. The geometrical domain consists of a cavity containing nanofluid that is driven by means of lid moving in one direction. This circulating nanofluid will extract enormous amount of heat from the solid block underneath the cavity resulting in conjugate heat transfer. A homogenous solver based on the finite volume method with conjugate heat transfer was developed and adopted in the existing study. The heat efficient hybrid nanofluid (HyNF) pair (2.4 vol.% Ag + 0.6 vol.% Al2O3) obtained by Nimmagadda and Venkatasubbaiah [1] is used in the present investigation. Moreover, efficient non-uniform sinusoidal magnetic field identified by Nimmagadda et al. [2] is also implemented and compared with uniform magnetic field. Furthermore, the magnetic field is applied over the geometrical domain along the two axial directions separately and the effective heat transfer performance is obtained. The significant impact of extensive parameters like Reynolds number, nanoparticle type, nanoparticle concentration, magnetic field type, magnetic field location and the strength of the magnetic field on heat transfer performance are systematically analyzed and presented.

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Hydrothermal and Entropy Investigation of Ag/MgO/H2O Hybrid Nanofluid Natural Convection in a Novel Shape of Porous Cavity

Applied Sciences ◽

10.3390/app11041722 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1722

Author(s):

Nidal Abu-Libdeh ◽

Fares Redouane ◽

Abderrahmane Aissa ◽

Fateh Mebarek-Oudina ◽

Ahmad Almuhtady ◽

...

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Natural Convection ◽

Volume Fraction ◽

Solid Volume Fraction ◽

Hybrid Nanofluid ◽

The Finite Element Method ◽

Governing Equations ◽

Nanofluid Flow ◽

The Magnetic Field

In this study, a new cavity form filled under a constant magnetic field by Ag/MgO/H2O nanofluids and porous media consistent with natural convection and total entropy is examined. The nanofluid flow is considered to be laminar and incompressible, while the advection inertia effect in the porous layer is taken into account by adopting the Darcy–Forchheimer model. The problem is explained in the dimensionless form of the governing equations and solved by the finite element method. The results of the values of Darcy (Da), Hartmann (Ha) and Rayleigh (Ra) numbers, porosity (εp), and the properties of solid volume fraction (ϕ) and flow fields were studied. The findings show that with each improvement in the Ha number, the heat transfer rate becomes more limited, and thus the magnetic field can be used as an outstanding heat transfer controller.

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Dusty hybrid nanofluid flow over a shrinking sheet with magnetic field effects

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-01-2021-0081 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Iskandar Waini ◽

Anuar Ishak ◽

Ioan Pop ◽

Roslinda Nazar

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Transfer Rate ◽

Temporal Stability ◽

Dust Particles ◽

Shrinking Sheet ◽

Hybrid Nanofluid ◽

Nanofluid Flow ◽

Content Type ◽

The Magnetic Field

Purpose This paper aims to examine the Cu-Al2O3/water hybrid nanofluid flow over a shrinking sheet in the presence of the magnetic field and dust particles. Design/methodology/approach The governing partial differential equations for the two-phase flow of the hybrid nanofluid and the dust particles are reduced to ordinary differential equations using a similarity transformation. Then, these equations are solved using bvp4c in MATLAB software. The bvp4c solver is a finite-difference code that implements the three-stage Lobatto IIIa formula. The numerical results are gained for several values of the physical parameters. The effects of these parameters on the flow and the thermal characteristics of the hybrid nanofluid and the dust particles are analyzed and discussed. Later, the temporal stability analysis is used to determine the stability of the dual solutions obtained as time evolves. Findings The outcome shows that the flow is unlikely to exist unless satisfactory suction strength is imposed on the shrinking sheet. Besides, the heat transfer rate on the shrinking sheet decreases with the increase of . However, the increase in and lead to enhance the heat transfer rate. Two solutions are found, where the domain of the solutions is expanded with the rising of, and. Consequently, the boundary layer separation on the surface is delayed in the presence of these parameters. Implementing the temporal stability analysis, it is found that only one of the solutions is stable as time evolves. Originality/value The dusty fluid problem has been widely studied for the flow over a stretching sheet, but only limited findings can be found for the shrinking counterpart. Therefore, this study considers the problem of the dusty fluid flow over a shrinking sheet containing Cu-Al2O3/water hybrid nanofluid with the effect of the magnetic field. In fact, this is the first study to discover the dual solutions of the dusty hybrid nanofluid flow over a shrinking sheet. Also, further analysis shows that only one of the solutions is stable as time evolves.

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A numerical study of the effect of the magnetic field on turbulent fluid flow, heat transfer and entropy generation of hybrid nanofluid in a trapezoidal enclosure

The European Physical Journal Plus ◽

10.1140/epjp/i2019-12681-3 ◽

2019 ◽

Vol 134 (6) ◽

Cited By ~ 9

Author(s):

Alireza Aghaei ◽

Hossein Khorasanizadeh ◽

Ghanbar Ali Sheikhzadeh

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Fluid Flow ◽

Entropy Generation ◽

Numerical Study ◽

Hybrid Nanofluid ◽

Turbulent Fluid Flow ◽

Flow Heat ◽

Trapezoidal Enclosure ◽

The Magnetic Field

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Numerical Analysis of Magnetic Field and Heat Transfer of a Reciprocating Magnetocaloric Regenerator Using a Halbach Magnet Array

Journal of Heat Transfer ◽

10.1115/1.4047368 ◽

2020 ◽

Vol 142 (9) ◽

Author(s):

Tunahan Akış ◽

Abdullatif Hamad ◽

Mehmet Akif Ezan ◽

Erim Yanık ◽

Ahmet Yılancı ◽

...

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Pressure Difference ◽

Thermal Analyses ◽

Temperature Drop ◽

Reynolds Numbers ◽

Heat Transfer Fluid ◽

Ansys Fluent ◽

Fluent Software ◽

The Magnetic Field

Abstract In this study, a numerical model of a reciprocating magnetocaloric regenerator using a Halbach magnet array is developed in ansys-fluent software. The model consists of three components, namely, (i) the Halbach magnet array, (ii) the magnetocaloric material (MCM), and (iii) the heat transfer fluid. A two-dimensional (2D) domain is studied due to the axisymmetric geometry of the physical model. A pressure difference is defined between the inlet and outlet sections of the fluid domain to maintain a reciprocating fluid flow. In the proposed computational scheme, a segregated approach is followed to consider the spatial distribution of the magnetic field in the thermal analyses. Therefore, a 2D magnetic field within the MCM is computed using an analytical approach at first, and its results are integrated into ansys-fluent with a user-defined function (UDF). Hydrodynamic and heat transfer characteristics of the proposed regenerator model are evaluated under various Reynolds numbers and cycle durations. Moreover, the temperature drop at the cold side of the regenerator is represented in terms of the pressure difference, flow duration, and the diameter of Gadolinium (Gd) as the MCM. For the current geometrical configurations, it is observed that the magnetic field varies from 0.4 T to 1 T within Gd. The highest temperature spans are measured as 8.4 K, 7.5 K, and 7.2 K numerically for the cycle durations of 1.2 s, 2.2 s, and 4.2 s, respectively.

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Natural convection analysis flow of Al2O3-Cu/water hybrid nanofluid in a porous conical enclosure subjected to the magnetic field

The European Physical Journal Applied Physics ◽

10.1051/epjap/2020200260 ◽

2020 ◽

Vol 92 (1) ◽

pp. 10904 ◽

Cited By ~ 1

Author(s):

Rabeh Slimani ◽

Abderrahmane Aissa ◽

Fateh Mebarek-Oudina ◽

Umair Khan ◽

M. Sahnoun ◽

...

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Nusselt Number ◽

Natural Convection ◽

Volume Fraction ◽

Convection Heat Transfer ◽

Darcy Number ◽

Hybrid Nanofluid ◽

Porosity Ratio ◽

The Magnetic Field

The current study investigates MHD natural convection heat transfer of a hybrid nanofluid in a truncated cone along with transparent domains having the stimulus of an inherent constant magnetic field. The governing equations subject to the physical boundary conditions are solved numerically by using the Galerkin finite element method. The effects of the various parameters involved in the problem such as the Rayleigh number Ra (ranging between 103 and 106), the Hartmann number Ha (ranging between 0 and 60), and the porosity ratio ε (0.1–0.9) are examined. Moreover, the effects of Da which represents the Darcy number (between 10‑3 and 10‑1) and the volume fraction of nanoparticles ϕ for the dissipated nanoparticles of Al2O3-Cu are reported in terms of the streamlines and isotherms distributions as well as the Nusselt number. Such parameters are critical control parameters for both the fluid flow and the rate of heat transfer of the natural convection in the annular space. The solution outcomes proof that the average Nusselt number varies directly with the dynamic field flowing through a porous media, whereas it behaves inversely with the magnetic field.

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Thermodynamic Analysis of Magnetic Refrigerators

Advanced Energy Systems ◽

10.1115/imece2004-61369 ◽

2004 ◽

Cited By ~ 4

Author(s):

Muhammad M. Rahman ◽

Luis Rosario

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Heat Exchangers ◽

Room Temperature ◽

Fluid Flows ◽

Heat Transfer Fluid ◽

Cooling Power ◽

Refrigeration Cycle ◽

Heating Effects ◽

The Magnetic Field

An analysis of a magnetic refrigeration cycle was carried out. The system consists of heat exchangers and beds of magnetic materials. The analysis considered that the system operates near room temperature in a magnetic field between 1 and 5 T and uses 3 kg of gadolinium (Gd) spheres packed in two magnetocaloric beds. The heat transfer fluid is water. The beds are periodically magnetized and demagnetized and the fluid flows are arranged to meet the cycle requirements. Sensitivity analysis has been performed. Cooling power, magnetic field, and temperature span trends are simulated. The cooling and heating effects were estimated based on the magnetocaloric effect of gadolinium. Findings indicate that the higher the magnetic field is the higher the cooling power with the same temperature span. It was also observed that the cooling power decreases with the increase in the temperature span for various magnetic fields. COP vs. temperature span was also considered. The trend indicates that COPactual/ COPCarnot decreases with an increase in the temperature span. These trends agreed with those shown by experimental data.

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Effects of uniform or non-uniform heating at bottom wall on MHD mixed convection in a porous cavity saturated by nanofluid

International Journal of Nonlinear Sciences and Numerical Simulation ◽

10.1515/ijnsns-2017-0258 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Subramanian Muthukumar ◽

Selvaraj Sureshkumar ◽

Arthanari Malleswaran ◽

Murugan Muthtamilselvan ◽

Eswari Prem

Keyword(s):

Magnetic Field ◽

Heat Transfer ◽

Transfer Rate ◽

Hartmann Number ◽

Volume Fraction ◽

Solid Volume Fraction ◽

Darcy Number ◽

Bottom Wall ◽

Uniform Heating ◽

The Magnetic Field

Abstract A numerical investigation on the effects of uniform and non-uniform heating of bottom wall on mixed convective heat transfer in a square porous chamber filled with nanofluid in the appearance of magnetic field is carried out. Uniform or sinusoidal heat source is fixed at the bottom wall. The top wall moves in either positive or negative direction with a constant cold temperature. The vertical sidewalls are thermally insulated. The finite volume approach based on SIMPLE algorithm is followed for solving the governing equations. The different parameters connected with this study are Richardson number (0.01 ≤ Ri ≤ 100), Darcy number (10−4 ≤ Da ≤ 10−1), Hartmann number (0 ≤ Ha ≤ 70), and the solid volume fraction (0.00 ≤ χ ≤ 0.06). The results are presented graphically in the form of isotherms, streamlines, mid-plane velocities, and Nusselt numbers for the various combinations of the considered parameters. It is observed that the overall heat transfer rate is low at Ri = 100 in the positive direction of lid movement, whereas it is low at Ri = 1 in the negative direction. The average Nusselt number is lowered on growing Hartmann number for all considered moving directions of top wall with non-uniform heating. The low permeability, Da = 10−4 keeps the flow pattern same dominating the magnetic field, whereas magnetic field strongly affects the flow pattern dominating the high Darcy number Da = 10−1. The heat transfer rate increases on enhancing the solid volume fraction regardless of the magnetic field.

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