A numerical study on heat transfer of a ferrofluid flow in a square cavity under simultaneous gravitational and magnetic convection

This paper presents a numerical study of heat transfer by convection in a square cavity. The vertical walls of the cavity are differentially heated and the horizontal ones are considered adiabatic. A fan is placed in the middle of the cavity and releases a jet down. Numerical simulation was performed using the lattice Boltzmann method to show the flow patterns and the heat flux depending on the Rayleigh number (thermal convection intensity) and the Reynolds number (fan-driven flow intensity). A parametric study was performed presenting the influence of Reynolds number (20 ≤ Re ≤ 500), Rayleigh number (10 ≤ Ra ≤ 106) and the fan position (0.2 ≤ HF ≤ 0.8). In forced convection mode, the flow structure has been mapped according to the position and the power of the fan. Three structures have emerged: two symmetrical cells, four symmetrical cells and asymmetrical structure. It has been observed that the heat transfer rate increases with the rise of Reynolds number and the reduction of the distance of the fan position from the ceiling. For the latter one, an unfavorable evolution of Nusselt number is observed for Ra > 104.

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Influence of Non Uniform Boundary Conditions on Laminar Free Convection in Wavy Square Cavity With Partial Partitions

Volume 1 ◽

10.1115/esda2004-58228 ◽

2004 ◽

Cited By ~ 1

Author(s):

A. Sabeur-Bendehina ◽

M. Aounallah ◽

L. Adjlout ◽

O. Imine ◽

B. Imine

Keyword(s):

Heat Transfer ◽

Boundary Conditions ◽

Numerical Study ◽

Laminar Regime ◽

Uniform Temperature ◽

Square Cavity ◽

Vertical Walls ◽

The Mean ◽

Rayleigh Numbers ◽

Partial Partitions

In the present work, a numerical study of the effect of non uniform boundary conditions on the heat transfer by natural convection in cavities with partial partitions is investigated for the laminar regime. This problem is solved by using the partial differential equations which are the equation of mass, momentum and energy. The tests were performed for different boundary conditions and different Rayleigh numbers while the Prandtl number was kept constant. Four geometrical configurations were considered namely three and five undulations with increasing and decreasing partition length. The results obtained show that the non uniform temperature in the vertical walls affects the flow and the heat transfer. The mean Nusselt number decreases comparing with the heat transfer in the undulated square cavity without partitions for all non uniform boundary conditions tested.

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Numerical study of natural convection heat transfer for second-grade fluids confined in square cavity subjected to horizontal heat flux

10.1063/5.0049421 ◽

2021 ◽

Author(s):

Hamza Daghab ◽

Mourad Kaddiri ◽

Said Raghay ◽

Mohamed Lamsaadi ◽

Hassan El Harfi

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Natural Convection ◽

Numerical Study ◽

Convection Heat Transfer ◽

Second Grade ◽

Natural Convection Heat Transfer ◽

Convection Heat ◽

Square Cavity ◽

Second Grade Fluids

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Effect of radiation on the flow structure and heat transfer in a 2-D gray medium

Thermal Science ◽

10.2298/tsci180108117r ◽

2019 ◽

Vol 23 (6 Part A) ◽

pp. 3603-3614

Author(s):

Nesrine Rachedi ◽

Madiha Bouafia ◽

Messaoud Guellal ◽

Saber Hamimid

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Natural Convection ◽

Average Nusselt Number ◽

Radiative Transfer Equation ◽

Numerical Study ◽

Discrete Ordinates ◽

Square Cavity ◽

Discrete Ordinates Method ◽

Gray Medium

A numerical study of combined natural convection and radiation in a square cavity filled with a gray non-scattering semi-transparent fluid is conducted. The horizontal walls are adiabatic and the vertical are differentially heated. Convection is treated by the finite volumes approach and the discrete ordinates method is used to solve radiative transfer equation using S6 order of angular quadrature. Representative results illustrating the effects of the Rayleigh number, the optical thickness and the Planck number on the flow and temperature distribution are reported. In addition, the results in terms of the average Nusselt number obtained for various parametric conditions show that radiation modifies significantly the thermal behavior of the fluid within the enclosure.

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Prandtl Number Effects on the Entropy Generation During the Transient Mixed Convection in a Square Cavity Heated from Below

Periodica Polytechnica Mechanical Engineering ◽

10.3311/ppme.17563 ◽

2021 ◽

Author(s):

Nawal Ferroudj ◽

Hasan Koten ◽

Sacia Kachi ◽

Saadoun Boudebous

Keyword(s):

Heat Transfer ◽

Prandtl Number ◽

Mixed Convection ◽

Entropy Generation ◽

Numerical Study ◽

Convection Heat Transfer ◽

Working Fluid ◽

Square Cavity ◽

Nusselt Numbers ◽

The Impact

This numerical study considers the mixed convection, heat transfer and the entropy generation within a square cavity partially heated from below with moving cooled vertical sidewalls. All the other horizontal sides of the cavity are assumed adiabatic. The governing equations, in stream function–vorticity form, are discretized and solved using the finite difference method. Numerical simulations are carried out, by varying the Richardson number, to show the impact of the Prandtl number on the thermal, flow fields, and more particularly on the entropy generation. Three working fluid, generally used in practice, namely mercury (Pr = 0.0251), air (Pr = 0.7296) and water (Pr = 6.263) are investigated and compared. Predicted streamlines, isotherms, entropy generation, as well as average Nusselt numbers are presented. The obtained results reveal that the impact of the Prandtl number is relatively significant both on the heat transfer performance and on the entropy generation. The average Nusselt number increase with increasing Prandtl number. Its value varies thereabouts from 3.7 to 3.8 for mercury, from 5.5 to 13 for air and, from 12.5 to 15 for water. In addition, it is found that the total average entropy generation is significantly higher in the case of mercury (Pr«1) and water (Pr»1) than in the case of air (Pr~1). Its value varies approximately from 700 to 1100 W/m3 K for mercury, from 200 to 500 W/m3 K for water and, from 0.03 to 5 W/m3 K for air.

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Free Convection in an Inclined Square Cavity With Partial Partitions on a Wavy Hot Wall

Volume 1 ◽

10.1115/esda2004-58251 ◽

2004 ◽

Author(s):

M. Belkadi ◽

A. Azzi ◽

O. Imine ◽

L. Adjlout ◽

M. Aounallah ◽

...

Keyword(s):

Heat Transfer ◽

Free Convection ◽

Numerical Study ◽

Wavy Wall ◽

Square Cavity ◽

Inclination Angles ◽

The Mean ◽

Rayleigh Numbers ◽

Partial Partitions ◽

Wall Geometry

In the present investigation, a numerical study of the effect of the hot wavy wall with partial partitions on free convection in an inclined square cavity, differentially heated, was undertaken. This problem is solved by using the partial differential equations which are the equation of mass, momentum, and energy. The tests were performed for different inclination angles, partition lenghts and Rayleigh numbers while the Prandtl number was kept constant. A configuration with three undulations and three partitions has been tested. The results obtained show that the hot wall geometry with partions affects the heat transfer rate in the cavity. The mean Nusselt number decreases notably compared with the heat transfer in the square undulated cavity without partitions.

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