scholarly journals Numerical Study of Periodic Magnetic Field Effect on 3D Natural Convection of MWCNT-Water/Nanofluid with Consideration of Aggregation

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 957 ◽  
Author(s):  
Lioua Kolsi ◽  
Hakan Oztop ◽  
Kaouther Ghachem ◽  
Mohammed Almeshaal ◽  
Hussein Mohammed ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Numerical Study ◽  
Three Dimensional ◽  
Magnetic Field Effect ◽  
Oscillation Period ◽  
Governing Equations ◽  
Periodic Magnetic Field ◽  
Aggregation Effect ◽  
Volume Method ◽  
The Magnetic Field

In this paper, a numerical study is performed to investigate the effect of a periodic magnetic field on three-dimensional free convection of MWCNT (Mutli-Walled Carbone Nanotubes)-water/nanofluid. Time-dependent governing equations are solved using the finite volume method under unsteady magnetic field oriented in the x-direction for various Hartmann numbers, oscillation periods, and nanoparticle volume fractions. The aggregation effect is considered in the evaluation of the MWCNT-water/nanofluid thermophysical properties. It is found that oscillation period, the magnitude of the magnetic field, and adding nanoparticles have an important effect on heat transfer, temperature field, and flow structure.

scholarly journals Effect of thermally active zones and direction of magnetic field on hydromagnetic convection in an enclosure

2011 ◽  
Vol 15 (suppl. 2) ◽  
pp. 367-382 ◽  
Author(s):  
Sivanandam Sivasankaran ◽  
Marimuthu Bhuvaneswari
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Average Nusselt Number ◽  
Hartmann Number ◽  
Numerical Study ◽  
Governing Equations ◽  
Aspect Ratios ◽  
Active Zones ◽  
Volume Method ◽  
The Magnetic Field

The aim of the present numerical study is to investigate the effect of thermally active zones and direction of the external magnetic field on hydromagnetic convection in an enclosure. Nine different relative positions of the thermally active zones are considered. Top and bottom of the enclosure are adiabatic. The governing equations are solved by the finite volume method. The results are obtained for different directions of the external magnetic field, thermally active locations, Hartmann numbers, Grashof numbers and aspect ratios. It is observed that the heat transfer is enhanced for heating location is either at middle or at bottom of the hot wall while the cooling location is either at top or at middle of the cold wall. The flow field is altered when changing the direction of the magnetic field in the presence of strong magnetic field. The average Nusselt number decreases with an increase of the Hartmann number and increases with increase of the Grashof number and aspect ratio.

Numerical Study of a Vertical Solidification Process under Magnetic Field in Unsteady State

2010 ◽  
Vol 297-301 ◽  
pp. 254-262
Author(s):  
Sabrina Nouri ◽  
Mouhamed Benzeghiba ◽  
Ahmed Benzaoui
Keyword(s):  
Magnetic Field ◽  
Binary Alloy ◽  
Numerical Study ◽  
Magnetic Field Effect ◽  
Solidification Process ◽  
Computer Code ◽  
Thermosolutal Convection ◽  
Unsteady State ◽  
Vertical Solidification ◽  
The Magnetic Field

Numerical computation is achieved in an axisymmetric configuration to analyze the magnetic field effect on thermosolutal convection during vertical solidification of a binary alloy. The bath is exposed to a uniform temperature profile in unsteady state. During the growth three regions appear: liquid, mushy and solid zones. The mushy zone is assimilated to porous medium. A mathematical model of heat, momentum and solute transfer has been developed in primitive variables (pressure-velocity). A single domain approach (enthalpy method) is used to build the equations system. In this context, a computer code has been developed and validated with previous studies. The results in term of stream function and solute concentration show the strong effect of the magnetic field on the fluid flow and on the solutal stratification. The effects of magnetic field and melt convection intensity were demonstrated. The main results show that the quality of highly doped binary alloy crystals can be improved when the growth process occurs at low pulling rates and under a magnetic field.

scholarly journals The effect of an external magnetic field on the entropy generation in three-dimensional natural convection

2010 ◽  
Vol 14 (2) ◽  
pp. 341-352 ◽  
Author(s):  
Lioua Kolsi ◽  
Awatef Abidi ◽  
Naceur Borjini ◽  
Ben Aïssia
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
External Magnetic Field ◽  
Liquid Metal ◽  
Entropy Generation ◽  
Numerical Study ◽  
Three Dimensional ◽  
Laminar Natural Convection ◽  
The Magnetic Field

A 3-D original numerical study of entropy generation in the case of liquid metal laminar natural convection in a differentially heated cubic cavity and in the presence of an external magnetic field orthogonal to the isothermal walls is carried out. The effect of this field on the various types of irreversibilities is analyzed. It was observed that in the presence of a magnetic field the generated entropy is distributed on the entire cavity and that the magnetic field limits the 3-D character of the distribution of the generated entropy.

Numerical Study of Heat Transfer in Rectangular Fins for Different Cases of Thermo-Physical Properties

2021 ◽  
Vol 408 ◽  
pp. 83-98
Author(s):  
Imene Bennia ◽  
Tawfik Benabdallah ◽  
Samah Lounis
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Three Dimensional ◽  
Governing Equations ◽  
Unconditionally Stable ◽  
Additional Heat ◽  
Dimensional Simulation ◽  
Volume Method ◽  
Thermo Physical Properties ◽  
Calculation Code

The present work is a contribution to the development of a calculation code that determines the temperature field on fins having rectangular geometry for any bi-dimensional or three-dimensional simulation conditions. Different cases of simulations are presented. An implicit finite volume method, unconditionally stable, is extended in this study for the discretization of the governing equations. The representative results, validated by the Ansys code, show that the fin temperature increases with the increase of the temperature values selected as the boundary conditions, with the addition of a heat flow or any additional heat source. The numerical results are very consistent with the theory and the results obtained from commercialized codes. By increasing the diffusivity one converge more quickly towards the stationary solution. Upon reducing the fin size a very drastic shift occurs from the transient regime to a permanent one. In the case of a refinement of the mesh, the use of a very small epsilon ensures the convergence. Therefore, the results obtained in this study serve as basis of comparison with any other study on heat transfer on rectangular fins.

The Model for Calculation the Hall Effect Parameter

2004 ◽  
Vol 9 (2) ◽  
pp. 129-138
Author(s):  
J. Kleiza ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Mapping Method ◽  
Sample Thickness ◽  
System Of Nonlinear Equations ◽  
Specific Resistivity ◽  
Conformal Mapping Method ◽  
Effect Parameter ◽  
The Magnetic Field

A method for calculating the values of specific resistivity ρ as well as the product µHB of the Hall mobility and magnetic induction on a conductive sample of an arbitrary geometric configuration with two arbitrary fitted current electrodes of nonzero length and has been proposed an grounded. During the experiment, under the constant value U of voltage and in the absence of the magnetic field effect (B = 0) on the sample, the current intensities I(0), IE(0) are measured as well as the mentioned parameters under the effect of magnetic fields B1, B2 (B1 ≠ B2), i.e.: IE(β(i)), I(β(i)), i = 1, 2. It has been proved that under the constant difference of potentials U and sample thickness d, the parameters I(0), IE(0) and IE(β(i)), I(β(i)), i = 1, 2 uniquely determines the values of the product µHB and specific resistivity ρ of the sample. Basing on the conformal mapping method and Hall’s tensor properties, a relation (a system of nonlinear equations) between the above mentioned quantities has been found.

The magnetic field effect on heat-exchange characteristics and MHD resistance of lead-bismuth eutectic flow in the TOKAMAK blanket heat-sink systems

2013 ◽  
Vol 49 (1-2) ◽  
pp. 237-248
Author(s):  
A. V. Beznosov ◽  
O. O. Novozhilova ◽  
S. Yu. Savinov ◽  
M. V. Yarmonov ◽  
R. E. Alekseev
Keyword(s):  
Magnetic Field ◽  
Heat Exchange ◽  
Heat Sink ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Lead Bismuth Eutectic ◽  
The Magnetic Field

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

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