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Article
Publication date: 5 June 2017

Abderrahmane Baïri, Clara Ortega Hermoso, David San Martén Ortega, Iken Baïri and Zsolt Peter

This work deals with the case of the quad flat non-lead 64 (QFN64) electronic package generating a low power range ranging from 0.01 to 0.1W. It is installed on one side…

Abstract

Purpose

This work deals with the case of the quad flat non-lead 64 (QFN64) electronic package generating a low power range ranging from 0.01 to 0.1W. It is installed on one side of a printed circuit board (PCB) that can be inclined relative to the horizontal plane with an angle varying between 0° and 90° (horizontal and vertical positions, respectively). The surface temperature of the electronic assembly is subjected to air natural convection.

Design/methodology/approach

Calculations are done by means of the finite volume method for many configurations obtained by varying the generated power and the inclination angle.

Findings

The distribution of the surface temperature is determined on all the assembly areas (QFN and PCB). The study shows that the thermal behaviour of the electronic device is influenced by the generated power and the inclination angle. The 3D numerical survey leads to correlations allowing calculation of the average surface temperature in any part of the assembly, according to the power generated by the QFN64 and the inclination angle.

Originality/value

The proposed accurate correlations are original and unpublished. They optimize the thermal design of the electronic QFN64 package, which is increasingly used in many engineering fields.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 7 November 2016

Abderrahmane Baïri, David San Martin, Iken Baïri, Kemi Adeyeye, Kaiming She, Ali Hocine, Nacim Alilat, Cyril Lamriben, Jean-Gabriel Bauzin, Bruno Chanetz and Najib Laraqi

The purpose of this paper is to examine the details of the air mass flow and aerodynamical phenomena across a channel containing a large vertical axis wind turbine. The…

Abstract

Purpose

The purpose of this paper is to examine the details of the air mass flow and aerodynamical phenomena across a channel containing a large vertical axis wind turbine. The considered model reproduces as closely as possible the real assembly of the Sistan-type wind-mill whose top is open. The technical results of this work could be used for the restoration and operation of this assembly whose historical and architectural values are recognized.

Design/methodology/approach

Several inlet velocities into the channel are considered, taking into account the possible local wind resources. Calculations corresponding to Reynolds number varying between 8×105 and 4×106 are made by means of the finite volume method and turbulence is treated with the realizable k-ε model. The mesh consists of a fixed part associated to the contour of the channel, interfaced with a moving one linked to the turbine itself, equipped with nine partly filled wings.

Findings

The relative pressure and velocity fields are presented for various dynamic and static conditions. Calculation results clearly show that the vortex phenomena present in some cases are not a source of degradation of the wind turbine’s aerodynamical performances, given its location, intensity and rotation direction. Particular attention is devoted to the air mass flow and its distribution between the inlet and the outlet sections of the channel.

Originality/value

The present work provides technical information useful to consider the restoration and modernization of this installation whose architecture and technical performance are very interesting. This survey complements a previous one examining the aerodynamical phenomena occurring in a modified version of this assembly with a closed top channel.

Details

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

Keywords

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Article
Publication date: 5 June 2017

Abderrahmane Baïri, Nacim Alilat, Ali Hocine, Abderrezak Hamouda and Oriana Haddad

The wire-bonded version of the quad flat non-lead with 64 leads (QFN64b) is increasingly integrated in modern arrangements, given its thermal and electrical…

Abstract

Purpose

The wire-bonded version of the quad flat non-lead with 64 leads (QFN64b) is increasingly integrated in modern arrangements, given its thermal and electrical characteristics suited for specific applications. Temperature control is thus essential for its proper operation, particularly when the heat exchange with the environment is done by natural convection. This work aims to consider a conventional assembly consisting of a large printed circuit board (PCB) on which is welded a QFN64b generating a power in the range 0.01-0.1 W. The PCB could be inclined at an angle varying between 0° and 90° (horizontal and vertical positions, respectively) according to the intended application.

Design/methodology/approach

The 3D numerical approach done by means of the finite volume method is complemented by thermal and electrical measurements for all the configurations numerically processed. The low deviations obtained between the calculations and the measurements validate the adopted model. These results complement recent work that considers the same assembly equipped with a tilted and low-powered QFN64 basic model subjected to free convection.

Findings

The surface temperature in any part of the assembly has been determined. The influence of the power generated by the device and the PCB’s inclination angle relative to the gravity field have been quantified. The work shows that the radiative heat transfer is negligible given the temperatures reached and that the thermal state of the considered assembly is different from the one equipped with the QFN64 basic model. The QFN’s temperature is lowered, while that of the PCB is increased. The temperature distribution is also different from that of assemblies equipped with other QFN models with and without wire-bonding.

Originality/value

The correlations proposed in this survey help optimize the thermal design of the QFN64b electronic package used in many engineering fields.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 6
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 7 February 2019

Abderrahmane Baïri, Nagaraj Suresh, Palanisamy Gayathri, Nagarajan Nithyadevi and Purusothaman Abimanyu

A porous medium saturated with a nanofluid based on pure water and copper nanoparticles is used for cooling a hemispherical electronic device contained in an annulus…

Abstract

Purpose

A porous medium saturated with a nanofluid based on pure water and copper nanoparticles is used for cooling a hemispherical electronic device contained in an annulus space. The disc of the cavity could be inclined at an angle ranging from 0 ° (horizontal disc with dome facing upwards) to 180° (horizontal disc with dome facing downwards). The important surface heat flux generated by the dome leads to high Rayleigh number values reaching 7.29 × 10^10. The purpose of this work is to examine the influence of the nanofluid saturated porous medium on the free convective heat transfer.

Design/methodology/approach

Heat transfer occurring between this active component and the isothermal passive cupola is quantified by means of a three-dimensional numerical study using the control volume method associated to the SIMPLE algorithm.

Findings

The work shows that heat transfer in the annulus space is improved by interposing a porous medium saturated with the water-copper nanofluid.

Originality/value

New correlation is proposed to calculate the Nusselt number for any combination of the inclination angle, the fraction volume, the Rayleigh number and the ratio between the thermal conductivities of the porous medium and the fluid. The wide ranges corresponding to these parameters allow the thermal design of this electronic equipment for various configurations.

Details

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

Keywords

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Article
Publication date: 7 November 2016

Abimanyu Purusothaman, Abderrahmane Baïri and Nagarajan Nithyadevi

The purpose of this paper is to examine numerically the natural convection heat transfer in a cubical cavity induced by a thermally active plate. Effects of the plate size…

Abstract

Purpose

The purpose of this paper is to examine numerically the natural convection heat transfer in a cubical cavity induced by a thermally active plate. Effects of the plate size and its orientation with respect to the gravity vector on the convective heat transfer and the flow structures inside the cavity are studied and highlighted.

Design/methodology/approach

The numerical code is based on the finite volume method with semi-implicit method for pressure-linked equation algorithm. The convective and diffusive terms in momentum equations are handled by adopting the power law scheme. Finally, the discretized sets of algebraic equations are solved by the line-by-line tri-diagonal matrix algorithm.

Findings

The results show that plate orientation and size plays a significant role on heat transfer. Also, the heat transfer rate is an increasing function of Rayleigh number for both orientations of the heated plate. Depending on the thermal management of the plate and its application (as in electronics), the heat transfer rate is maximized or minimized by selecting appropriate parameters.

Research limitations/implications

The flow is assumed to be 3D, time-dependent, laminar and incompressible with negligible viscous dissipation and radiation. The fluid properties are assumed to be constant, except for the density in the buoyancy term that follows the Boussinesq approximation.

Originality/value

The present work will give some additional knowledge in designing sealed cavities encountered in some engineering applications as in aeronautics, automobile, metallurgy or electronics.

Details

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

Keywords

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Article
Publication date: 30 October 2018

Abderrahmane Baïri, Jean-Gabriel Bauzin, Alexander Martín-Garín, Nacim Alilat and José Antonio Millán-García

The purpose of this study is to determine the thermal behavior of a hemispherical electronic device contained in a concentric hemispherical enclosure, cooled by means of…

Abstract

Purpose

The purpose of this study is to determine the thermal behavior of a hemispherical electronic device contained in a concentric hemispherical enclosure, cooled by means of free convection through a porous medium saturated with a water–copper nanofluid. Influence of various parameters on the thermal state of this device is processed in this work. The high power generated by the dome leads to a Rayleigh number varying in the 5.2 × 107-7.29 × 1010 range. The volume fraction of the monophasic nanofluid varies between 0 (pure water) and 10 per cent while the base of the hemispherical cavity (disc) is inclined between 0° (horizontal disc with dome facing upward) and 180° (horizontal disc with dome facing downward).

Design/methodology/approach

The three-dimensional numerical approach is carried out by means of the volume control method associated to the SIMPLE algorithm.

Findings

The work shows that the average temperature of the active component increases with the Rayleigh number according to a conventional law of the power type. The increase in the angle of inclination also goes with a systematic rise in the average temperature. However, increasing the ratio of the solid–fluid thermal conductivities decreases the average temperature of the component, given the respective contributions of the conductive and natural convective phenomena occurring through the nanofluid saturated porous media. The values of this ratio vary in this work between 0 (interstice between the two hemispheres without porous medium) and 70.

Originality/value

The correlation proposed in this work allows to calculate the temperature of the active electronic component for all the combinations of the four influence parameters which vary in wide ranges.

Details

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

Keywords

Abstract

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 26 no. 7
Type: Research Article
ISSN: 0961-5539

Content available
Article
Publication date: 8 May 2018

Abderrahmane Baïri, Jean Delery and Bruno Chanetz

Abstract

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 28 no. 5
Type: Research Article
ISSN: 0961-5539

Content available
Article
Publication date: 10 March 2021

Abderrahmane Baïri, Jean Delery and Bruno Chanetz

Abstract

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 2
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 7 April 2015

Abderrahmane Baïri

Nusselt-Rayleigh-Fourier type correlations are proposed to quantify the temporal evolution of convective heat transfer occurring within air-filled hemispherical enclosures…

Abstract

Purpose

Nusselt-Rayleigh-Fourier type correlations are proposed to quantify the temporal evolution of convective heat transfer occurring within air-filled hemispherical enclosures whose disk, initially at ambient temperature, is suddenly maintained at a higher temperature. The temperature difference imposed between this hot wall and the isothermal cold dome involves Rayleigh number varying between 104 and 2.55×1012. Depending on the application, the disk can be inclined with respect to the horizontal plane by an angle varying between 0° (horizontal disk) and 90° (vertical disk) in steps of 15°. The paper aims to discuss these issues.

Design/methodology/approach

The results are obtained by means of a numerical approach based on the finite volume method. The proposed correlations linked to the steady state Nusselt-Rayleigh internships recently published, concerning the same inclination angle and Rayleigh ranges.

Findings

The statistical analysis of a large number of calculations leads to reliable results covering laminar, transitional and turbulent natural convection heat transfer zones.

Practical implications

The proposed relationships can be applied in several engineering fields such as nuclear technology, solar energy, security and safety electronics, building, domotics or aeronautics.

Originality/value

The new relationships proposed in this paper provide important information on the evolution of convective heat transfer during the transient regime.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 25 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

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