Hacen Dhahri

• Professor
• Head of Department at University of Monastir

Using the RANS approach with the standard k-ω turbulence model, this study offers a novel investigation into the dynamic and thermal properties of turbulent impinging jet arrays. Our study examines the combined effect of the number of jets (N) and the jet–jet spacing (S) on flow mechanisms and heat transfer performance, which is unique compared to...

It is anticipated that fuel cells technologies will have a considerable role in the sustainable and productive energy system in the future owing to their elevated energy efficiency and fuel flexibility. Recently, the progress for fuel cells has gone quickly. However these technologies are in their early development stage, although, the potential is...

In this study, a numerical investigation of a magneto-hydrodynamic (MHD) and backward-facing nanofluidic flow was performed using the thermal lattice Boltzmann method (LBM) with multiple distribution functions to handle dynamic and thermal fields, including the magnetic force. The Cu-H₂O based nanofluid is considered as the working fluid...

This study aims to numerically reveal and assess the influence of inserts of different shapes partially obstructing the anode flow channel on flow characteristics, heat and mass transfer, and planar solid oxide fuel cell (SOFC) performance. To this end, a lattice‐based Boltzmann method is taken. Within this setting, trapezoidal, circular, and trian...

In this work, latent heat thermal energy storage system composed of porous metal foams with phase change material subject to pulsating fluid flow is investigated. The pulsating admission of such systems has not been thoroughly studied so far. Thus, the main motivation of the present study has been the investigation of the effect of pulsating admiss...

A thorough understanding of the solid oxide fuel cell (SOFC) performance and reactants' distribution through modeling and numerical simulation has become essential. In this paper, a comprehensive numerical model based on a lattice-based Boltzmann method was developed to numerically handle gas flow in the partially blocked channel and concentration...

This paper presents a mathematical model that deals with multi-effect desalination plants without thermal vapor compression. It was extensively investigated using data obtained from Zuara desalination plant. It is located 70 km west of Tripoli the capital city of Libya. The developed mathematical model was authenticated by the simulation of the fir...

Sharing renewable energies, reducing energy consumption and optimizing energy management in an attempt to limit environmental problems (air pollution, global warming, acid rain, etc.) has today become a genuine concern of scientific engineering research. Furthermore, with the drastic growth of requirements in building and industrial worldwide secto...

The streaming flow and convective heat transfer in a standing-wave thermoacoustic engine (SWTAE) filled with helium gas were numerically handled. The mathematical model depicting the flow and heat transfer occurring consists of the extended Brinkman–Forchheimer–Darcy equations under Boussinesq approximation and completed by the temperature equation...

Improving heat transfer using nanofluids has proven to be a promising option with many practical applications. However, the behavior of particles conveying energy for thermal transport depends closely on the dimensions of systems and channels where the flow evolves. Thereby, any fine thermal analysis should lean on a mesoscale approach applied at a...

Water and energy are the main two requisites for any prosperous life. The massive population growth, high living standards, and rapid industrial and agricultural development are all contributing to water scarcity and high-energy demand. In this paper, a literature review of the initial operations and basic principles of various desalination systems...

In the context of attempts to improve the performance of solid oxide fuel cell (SOFC), we investigate whether -and to which degree - pulsating flow in the cathode channel affects the performance of the fuel cell. In this study, a two-dimensional Lattice Boltzmann, non-isothermal model of planar SOFC is developed for simulating multicomponent gas tr...

In this investigation, a comprehensive numerical analysis of the flow involved in an open-ended straight channel fully filled with a porous metal foam saturated and a phase change material (paraffin) has been performed using a single relaxation time lattice Boltzmann method (SRT-LBM) at the representative elementary volume (REV) scale. The enthalpy...

Numerical simulation reported on heat transfer and fluid flow in a two-dimensional rectangular micro channel totally filled with Ag/water. The first –order slip/jump boundary conditions were uniformly imposed to the up and bottom walls. The governing conservation equations are translated in dimensionless form using the thermal Single Relaxation Tim...

In this work, an unsteady forced convection heat transfer in an open-ended channel incorporating a porous medium filled either with a phase change material (PCM; case 1) or with water (case 2) has been studied using a thermal lattice Boltzmann method (TLBM) at the representative elementary volume (REV) scale. The set of governing equations includes...

Mathematical thermodynamic modeling is used in desalination systems to obtain unknown values and predict various properties such as enthalpy or phase equilibrium. These models are useful to understand system behavior. Zuara desalination plant is a multi-effect evaporation plant without vapor pressure (MED) with three total units of 40,000 m3/day. A...

A complete electrochemical model is developed and calibrated on experiments to validate the numerical data. The fitting parameters extracted from the calibration study are used to validate the current-voltage characteristic of an SOFC tested with both H2/H2O and H2/N2 mixtures. Moreover, the effects of hydrogen molar fraction, fuel flow rate and op...

The present contribution deals with an analysis of the effects of heat sources on temperature field inside SOFC components (channels cathode, anode and electrolyte). Heat sources in SOFCs include ohmic heat losses, activation heat losses, concentration heat losses and the heat released by chemical processes. The temperature distribution is investig...

A numerical analysis was carried out of mixed convection heat transfer for a laminar flow in a rectangular inclined microchannel totally filled with a water/Al2O3 nanofluid. The governing conservation equations are translated into a dimensionless form using the thermal single relaxation time and they modify the lattice Boltzmann method with double...

The current research expounds numerical investigation of key parameters effects, namely porosity ( ε= 0.4, 0.6, 0.7 and 0.8), Reynolds number ( Re = 100, 200, 400 and 600) and Eckert number ( Ec = 0, 1, 5 and 10) on the forced convective laminar flow and heat transfer through a horizontal porous channel filled with a metal foam structure impregnate...

This paper performs a numerical assessment of the porosity effect on heat transfer under forced convection in an open-ended horizontal channel filled with a porous structure and a phase change material (PCM). To take into account forced convection between the solid matrix and the PCM, the dimensionless Darcy-BrinkmanForchheimer equations and the lo...

This paper performs a numerical assessment of the porosity effect on heat transfer under forced convection in an open-ended horizontal channel filled with a porous structure and a phase change material (PCM). To take into account forced convection between the solid matrix and the PCM, the dimensionless Darcy-BrinkmanForchheimer equations and the lo...

In this work, the two-dimensional laminar flow and the heat transfer in an open-ended rectangular porous channel (metal foam) including a phase change material (PCM; paraffin) under forced convection were numerically investigated. To gain further insight into the foam pore effect on charging/discharging processes, the Darcy–Brinkmann–Forchheimer (D...

In this work, the two-dimensional laminar flow and the heat transfer in an open-ended rectangular porous channel (metal foam) including a phase change material (PCM; paraffin) under forced convection were numerically investigated. To gain further insight into the foam pore effect on charging/discharging processes, the Darcy–Brinkmann–Forchheimer (D...

This article proposes a numerical analysis for performance improvement of the stack, which represents a crucial element on the solar-powered thermoacoustic refrigerator. The stack is considered as a saturated parallelepiped homogeneous porous media. Numerical simulation of the flow and the heat transfer in the thermoacoustic refrigerator is carried...

This paper performs a numerical analysis of time-dependent forced convection heat transfer in an open-ended straight channel filled with a metal structure and paraffin as a phase change material (PCM). The unsteady two-dimensional governing equations, based on the Darcy-Brinkmann-Forchheimer (DBF) model and the two-energy transport equations (i.e....

This paper performs a numerical analysis of time-dependent forced convection heat transfer in an openended straight channel filled with a metal structure and paraffin as a phase change material (PCM). The unsteady two-dimensional governing equations, based on the Darcy-Brinkmann-Forchheimer (DBF) model and the two-energy transport equations (i.e. l...

In this paper, a design of a mini parabolic concentrator is studied. The interior surface is covered with a reflective layer and equipped with a cylindrical receiver in its focal position. To validate the sizing of the main parts of our system and to make our mechanism resistant against external forces, we used the numerical simulation carried out...

A numerical study of viscous dissipation effects on incompressible forced convection flow of nanofluids over a two dimensional horizontal backward facing-step (BFS) placed in a porous channel is carried out in a laminar flow regime. In the flow modeling, the Brinkman-Forchheimer extended Darcy model (DBLF) is incorporated in the momentum equation a...

The present paper deals with a numerical simulation of heat sources effects on temperature field inside a solid oxide fuel cell component. The temperature distribution is investigated using a co-flow planar SOFC comprising the air and fuel channel and two-ceramic electrodes, separated by an electrolyte. The Lattice Boltzmann Method is used for the...

A two-dimensional model based on the lattice Boltzmann method (LBM) is established to study the solid oxide fuel cell performance. A single-phase multicomponent model is used to describe mass transport in the porous electrodes and fuel/air channels. Our results are compared with those from the literature and a good agreement is found. After model v...

This paper treats an experimental and modeling study to predict the electrochemical performance of a Ni/YSZ supported planar SOFC with the air electrode made by LSFC-GDC. A complete electrochemical model is developed and calibrated on experiments to validate the numerical data. A detailed description is presented to show how the electrochemical par...

This paper treats an experimental and modeling study to predict the electrochemical performance of a Ni/YSZ supported planar SOFC with the air electrode made by LSFC-GDC. A complete electrochemical model is developed and calibrated on experiments to validate the numerical data. A detailed description is presented to show how the electrochemical par...

In this work entropy generation and heat transfer for magnetohydrodynamic (MHD) forced convection flow in a micro duct filled with a porous medium are investigated using a modified axisymmetric Lattice Boltzmann Method. In modeling the flow, the Brinkman–Forchheimer-extended Darcy model is incorporated in momentum equations. The Local Thermal Non-E...

This paper deals with heat transfer and fluid flow in a porous micro duct under local thermal non equilibrium conditions subjected to an external oriented magnetic field. The considered sample is a micro duct filled with porous media assumed to be homogenous, isotropic and saturated. The slip velocity and the temperature jump were uniformly imposed...

The present paper reports a numerical study to investigate the drying of rectangular gypsum sample based on a diffusive model. Both vertical and low sides of the porous media are treated as adiabatic and impermeable surfaces plate. The upper face of the plate represents the permeable interface. The energy equation model is based on the local therma...

Solar water heating systems prove to be an effective technology for converting solar energy into thermal energy. The efficiency of solar thermal conversion is important compared to solar electrical direct conversion systems. Therefore this paper improves numerically the thermal efficiency of solar water heaters wherein we try to improve the convect...

This paper deals with a thermodynamic analysis of sensible heat storage unit built by porous media. Analysis of the system's performances was tested through forced pulsating fluid flow, as thermal enhancement technique. Brinkman-Forchheimer-extended Darcy model is incorporated in momentum equations. Local thermal non-equilibrium (LTNE) between flui...

The present paper centered on a numerical investigation of irreversibility within a porous micro duct subjected to an external oriented magnetic field. At the wall, slip velocity and temperature jump are used as types of boundary conditions. The flow is described by Darcy-Brinkman-Forchheimer model. The Local Thermal Non Equilibrium (LTNE) is adopt...

The present contribution deals with an analysis of the effects of heat sources on temperature field inside SOFC components (channels cathode, anode and electrolyte). Heat sources in SOFCs include ohmic heat losses, activation heat losses, concentration heat losses and the heat released by chemical processes. The temperature distribution is investig...

The purpose of this work was to investigate numerically the drying of saturated deformable porous media. The considered sample is a rectangular porous plate which assumed to be both hydro-dynamically and thermally anisotropic, while the mechanical behavior of the sample is supposed to be isotropic. All walls of the plate are subjected to a convecti...

A numerical study of viscous dissipation effects on heat transfer, thermal energy storage by sensible heat and entropy generation within a porous channel with insulated walls was carried out in a laminar flow regime. The channel is subjected to the effect of a transverse magnetic field. In the flow modeling, the Brinkman-Forchheimer extended Darcy...

The convective drying of an anisotropic saturated deformable porous media has been carried out numerically in the present paper based on the Darcy-Brinkmann extended model. The considered sample is a porous medium that is assumed to be both hydro-dynamically and thermally anisotropic. All walls of the sample are subjected to a convective heat flux....

A numerical study is reported here to investigate the drying of saturated deformable porous rectangular plate based on the Darcy–Brinkman extended model. All walls of the plate are maintained to a convective heat flux as well as the top and bottom faces are also subjected to a mass flux. The model for the energy transport is based on the local ther...

The numerical study is centered around the drying of deformable porous media. The physical model used for simulation is a saturated isotropic deformable porous media. Walls of the considered sample are maintained to a convective heat flux. The sample is saturated with two phases, (solid and liquid phases). The water is evaporated via the top and bo...

A numerical study of the viscous dissipation effects on entropy generation for oscillating flow, within a cylinder filled with a porous medium and heated by a constant heat flux at the wall, was carried out in laminar flow regime. The flow is modelled by the Brinkman-Lapwood-Forchheimer-extended Darcy model (DBLF). The mathematical model for energy...

The present paper deals with numerical investigation of heat transfer and entropy generation for pulsating flow within a cylinder filled with a fluid-saturated porous medium with a wall maintained at constant heat flux. In modeling the flow, the Brinkman-Lapwood-Forchheimer-extended Darcy model is incorporated in momentum equations. Furthermore, th...

The laminar compressible flow in a pipe partially filled with porous media (a regenerator) is studied numerically during an expansion stroke. The computations are based on the finite-element-based control volume method for a moved grid, and the SIMPLER algorithm has been implemented. The physical model for the momentum conservation equation makes u...

The purpose of this study is to analyze the fluid flow and heat transfer in a pipe partially filled with porous media and provided with a flat piston during an expansion stroke. In addition to the Navier-Stokes equation for the fluid region, Brinkman-Forchheimer-Lapwood-extended Darcy’s model is introduced into the numerical solver to simulate flow...

In this paper, a numerical study of unsteady natural convection in a fluid-saturated porous medium bounded by two equal-thickness walls has been made. The porous medium is assumed to be both hydrodynamically and thermally anisotropic. The vertical walls are isothermal at different temperatures, the horizontal walls are adiabatic. For modeling fluid...

A model approach for heat and mass transfers during gas sorption by a zeolite bed is developed. The mathematical modeling is based on assuming the bed to be formed with three phases solid, liquid, and gaseous. The classical finite volume method is used to numerically solve the differential set of governing macroscopic equations. Numerical results p...

The aim of this paper is a numerical simulation of heat and moisture exchange properties of industrial helmet. In order to help designer to optimize the helmet thermal properties, the effect of thermal conductivity and liner thickness on the microclimate temperature is investigated. The liquid moisture diffusion in the comfort liner is modeled by t...

Le présent travail consiste à modéliser les transferts de chaleur et de masse dans un lit fixe lors de la désorption en considérant le milieu formé de trois phases différentes (phase liquide, une phase gazeuse et phase solide). Nous avons établit un code de calcul. Ce code nous a permis de déterminer l’évolution spatio-temporelle de la température...

The safety helmet comfort has been the field of steadily increasing interest. This paper is a numerical simulation of heat transfer from the head to the helmet microclimate and liners components. In order to help designer to optimize the helmet thermal properties, the effect of thermal conductivity and liner thickness on the microclimate temperatur...

A numerical study of a laminar piston-driven flow and heat transfer is made in a cylinder partially filled with a laterally heated saturated porous medium. The Brinkman-Lapwood-Forchheimer-extended Darcy model, with variable porosity, is used in the compressible momentum equations. For the energy equation, the local thermal equilibrium assumption i...

A numerical study of entropy generation for pulsating flow within a cylinder partially filled with a porous medium and exposed to a constant heat flux at the wall was carried out in the laminar flow regime. The porous substrate is attached to the inner side of the cylinder axis, while the upper side is filled with a pure fluid phase. The flow withi...

The aim of this paper is a numerical simulation of a forced pulsating laminar flow into a cylinder partially filled with a porous medium and the associated transport process. The porous substrate is attached to the inner side of the cylinder wall, which is exposed to a constant heat flux. The flow within the porous domain is modeled by the Brinkman...

A numerical investigation has been carried out for laminar incompressible reciprocating flow and heat transfer in a pipe filled with a porous medium and with a finite length. The pipe walls are assumed at constant temperature. A general model for the momentum equation was employed. The model for the energy transport was based on the local thermal e...

The present work is concerned with the rate of entropy generation due to flow and heat transfer by unsteady natural convection coupled with thermal radiation in a vertical channel opened at both ends and filled with anisotropic fluid saturated porous medium. In the present study the energy equation was derived assuming the local thermal equilibrium...

The present work involves the numerical simulation of forced pulsating flow into a cylinder containing simultaneously fluid region, porous region and fluid region and the associated transport process. The cylinder wall is adiabatic in the fluid regions and at constant heat flux in the porous region. A general model for the momentum equation was emp...