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Article
Publication date: 26 October 2018

Abdullah A.A.A. Al-Rashed, Lioua Kolsi, Mohammed A. Tashkandi, Emad Hasani Malekshah, Ali J. Chamkha and Mohamad Naceur Borjini

The purpose of this paper is to investigate the coupled effect of magnetic field and radiation on convective heat transfer of low electrically conductive dielectric oxide melt.

Abstract

Purpose

The purpose of this paper is to investigate the coupled effect of magnetic field and radiation on convective heat transfer of low electrically conductive dielectric oxide melt.

Design/methodology/approach

The 3D Navier–Stokes equations are formulated using the vector potential-vorticity formulation and solved using the finite volume method (FVM). The radiative heat transfer equation is discretized using the FTnFVM method. A code was written using FORTRAN language.

Findings

The obtained numerical results are focused on the effect of the different parameters on the heat transfer and the flow structure with a special interest on the 3D transvers flow. It is found that the flow is developing in inner spirals and the magnetic field intensifies this 3D character. The radiation acts mainly at the core of the enclosure and causes the apparition of the merging phenomenon near the front and back walls.

Originality/value

The effect of magnetic field on convective heat transfer of highly electrically conductive fluids has been intensively studied. Reciprocally, the case of a fluid with low electrical conductivity is not so much investigated, especially when it is coupled with the effect of radiation. These two effects are studied in this paper for the case of a low-conductive LiNbO3 oxide melt.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 7 November 2016

Lioua Kolsi, Nidal Abu-Hamdeh, Hakan F. Öztop, Abdulaziz Alghamdi, Borjini Mohamad Naceur and Habib Ben Assia

The purpose of this paper is to provide a solution for natural convection in a cavity with a partial heater in case of volumetric heating and analysis of the entropy generation.

Abstract

Purpose

The purpose of this paper is to provide a solution for natural convection in a cavity with a partial heater in case of volumetric heating and analysis of the entropy generation.

Design/methodology/approach

The control volume method based on three-dimensional (3D) vorticity-potential vector was applied to solve governing equations of natural convection in a 3D cavity with a fin for different governing parameters as external Rayleigh numbers (103=RaE=106), internal Rayleigh numbers 103=RaI=106, partition height (0.25=h=0.75) and partition location (0.25=c=0.75). A code was written by using Fortran platform.

Findings

The edge of the fin becomes important on entropy generation. The ratio of the RaI/RaE plays the important role on natural convection and entropy generation. The variation of external Rayleigh number becomes insignificant for the RaI/RaE>1.

Originality/value

The originality of this work is to analyze the entropy generation and natural convection in a cubical cavity with volumetrically heating.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 3 April 2017

Lioua Kolsi, Hakan F. Öztop, Nidal Abu-Hamdeh, Borjini Mohamad Naceur and Habib Ben Assia

The main purpose of this work is to arrive at a three-dimensional (3D) numerical solution on mixed convection in a cubic cavity with a longitudinally located triangular…

Abstract

Purpose

The main purpose of this work is to arrive at a three-dimensional (3D) numerical solution on mixed convection in a cubic cavity with a longitudinally located triangular fin in different sides.

Design/methodology/approach

The 3D governing equations are solved via finite volume technique by writing a code in FORTRAN platform. The governing parameters are chosen as Richardson number, 0.01 ≤ Ri ≤ 10 and thermal conductivity ratio 0.01 ≤ Rc ≤ 100 for fixed parameters of Pr = 0.7 and Re = 100. Two cases are considered for a lid-driven wall from left to right (V+) and right to left (V−).

Findings

It is observed that entropy generation due to heat transfer becomes dominant onto entropy generation because of fluid friction. The most important parameter is the direction of the moving lid, and lower values are obtained when the lid moves from right to left.

Originality

The main originality of this work is to arrive at a solution of a 3D problem of mixed convection and entropy generation for lid-driven cavity with conductive triangular fin attachments.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 January 2014

Hakan F. Oztop, Kolsi Lioua, Borjini Mohamad Naceur and Khaled Al-Salem

The main purpose of this paper is to conduct on three-dimensional buoyancy and thermocapillary convection in an enclosure. Entropy generation is obtained from the…

Abstract

Purpose

The main purpose of this paper is to conduct on three-dimensional buoyancy and thermocapillary convection in an enclosure. Entropy generation is obtained from the calculated values of velocities and temperatures.

Design/methodology/approach

As numerical method, the vorticity-vector potential formalism allows, in a three-dimensional configuration, the elimination of the pressure, which is a delicate term to treat. The control volume finite difference method is used to discretize equations. The central-difference scheme for treating convective terms and the fully implicit procedure to discretize the temporal derivatives are retained. The grid is uniform in all directions with additional nodes on boundaries. The successive relaxation iterating scheme is used to solve the resulting non-linear algebraic equations.

Findings

Results are presented via entropy generation due to heat transfer, entropy generation due to fluid friction and total entropy generation. It is found that Marangoni number becomes more effective parameter on total entropy generation for lower values of Rayleigh numbers.

Practical implications

In any thermal system under buoyancy induced and thermocapillary flow.

Originality/value

It is believed that this is the first paper on three-dimensional solution of entropy generation in a cubical cavity under thermocapillary buoyancy flow.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 2 November 2018

Alireza Rahimi, Abbas Kasaeipoor, Emad Hasani Malekshah, Mohammad Mehdi Rashidi and Abimanyu Purusothaman

This study aims to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with CuO-water nanofluid.

Abstract

Purpose

This study aims to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with CuO-water nanofluid.

Design/methodology/approach

The lattice Boltzmann method is used to solve the problem numerically. Two different multiple relaxation time (MRT) models are used to solve the problem. The D3Q7–MRT model is used to solve the temperature field, and the D3Q19 is used to solve the fluid flow of natural convection within the enclosure.

Findings

The influences of different Rayleigh numbers (103 < Ra < 106) and solid volume fractions (0 < f < 0.04) on the fluid flow, heat transfer, total entropy generation, local heat transfer irreversibility and local fluid friction irreversibility are presented comprehensively. To predict thermo–physical properties, dynamic viscosity and thermal conductivity, of CuO–water nanofluid, the Koo–Kleinstreuer–Li (KKL) model is applied to consider the effect of Brownian motion on nanofluid properties.

Originality/value

The originality of this work is to analyze the three-dimensional natural convection and entropy generation using a new numerical approach of dual-MRT-based lattice Boltzmann method.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 December 2018

Alireza Rahimi, Ali Dehghan Saee, Abbas Kasaeipoor and Emad Hasani Malekshah

The purpose of this paper is to carry out a comprehensive review of some latest studies devoted to natural convection phenomenon in the enclosures because of its…

Abstract

Purpose

The purpose of this paper is to carry out a comprehensive review of some latest studies devoted to natural convection phenomenon in the enclosures because of its significant industrial applications.

Design/methodology/approach

Geometries of the enclosures have considerable influences on the heat transfer which will be important in energy consumption. The most useful geometries in engineering fields are treated in this literature, and their effects on the fluid flow and heat transfer are presented.

Findings

A great variety of geometries included with different physical and thermal boundary conditions, heat sources and fluid/nanofluid media are analyzed. Moreover, the results of different types of methods including experimental, analytical and numerical are obtained. Different natures of natural convection phenomenon including laminar, steady-state and transient, turbulent are covered. Overall, the present review enhances the insight of researchers into choosing the best geometry for thermal process.

Originality/value

A comprehensive review on the most practical geometries in the industrial application is performed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 4 October 2018

Alireza Rahimi, Abbas Kasaeipoor, Emad Hasani Malekshah and Lioua Kolsi

This paper aims to perform the lattice Boltzmann simulation of natural convection heat transfer in cavities included with active hot and cold walls at the side walls and…

Abstract

Purpose

This paper aims to perform the lattice Boltzmann simulation of natural convection heat transfer in cavities included with active hot and cold walls at the side walls and internal hot and cold obstacles.

Design/methodology/approach

The cavity is filled with double wall carbon nanotubes (DWCNTs)-water nanofluid. Different approaches such as local and total entropy generation, local and average Nusselt number and heatline visualization are used to analyze the natural convection heat transfer. The cavity is filled with DWCNTs-water nanofluid and the thermal conductivity and dynamic viscosity are measured experimentally at different solid volume fractions of 0.01 per cent, 0.02 per cent, 0.05 per cent, 0.1 per cent, 0.2 per cent and 0.5 per cent and at a temperature range of 300 to 340 (K).

Findings

Two sets of correlations for these parameters based on temperature and solid volume fraction are developed and used in the numerical simulations. The influences of different governing parameters such as Rayleigh number, solid volume fraction and different arrangements of active walls on the fluid flow, heat transfer and entropy generation are presented, comprehensively. It is found that the different arrangements of active walls have pronounced influence on the flow structure and heat transfer performance. Furthermore, the Nusselt number has direct relationship with Rayleigh number and solid volume fraction. On the other hand, the total entropy generation has direct and reverse relationship with Rayleigh number and solid volume fraction, respectively.

Originality/value

The originality of this work is to analyze the two-dimensional natural convection using lattice Boltzmann method and different approaches such as entropy generation and heatline visualization.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

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