Soufien Belhaj | University of Tunis El Manar (original) (raw)
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Graduate Center of the City University of New York
Swiss Federal Institute of Technology (ETH) & University of Zurich
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Papers by Soufien Belhaj
Particulate Science and Technology, May 16, 2018
ABSTRACT Numerical unsteady natural convection flow in a square cavity in the presence of uniform... more ABSTRACT Numerical unsteady natural convection flow in a square cavity in the presence of uniform magnetic field is investigated. The cavity is filled with CNT-water nanofluid and heated from below with sinusoidal temperature distribution. This study has been conducted for the certain pertinent parameters of Rayleigh number Ra, Hartmann number Ha and the CNT volume fraction from Φ = 0 to 0.12. The results indicate, that for large values of Ha, increasing Φ results in an increase of the normalized average Nusselt number. The rate corresponding to CNT- volume fraction nanoparticles of 10% ensures an enhancement about 50% of the heat transfer rate compared to the standard case. The flow undergoes a period bifurcation at a Rayleigh number beyond the value 106. A critical Rayleigh number Rac of 1.077 × 106 is then computed. Finally, a correlation giving the average Nusselt number as a function of the frequency of the periodic regime is established.
Journal of Thermal Science and Technology, 2018
Paper No.17-00587 © 2018 The Japan Society of Mechanical Engineers [DOI: 10.1299/jtst.2018jtst001... more Paper No.17-00587 © 2018 The Japan Society of Mechanical Engineers [DOI: 10.1299/jtst.2018jtst0019] Abstract In this paper, heat transfer and entropy generation of MHD natural convection of Carbone NanoTube (CNT)water nanofluids in a square cavity with and without isothermal block are numerically studied. The cavity is heated sinusoidally, according to the X coordinate, from below and it is cooled isothermally from the top. The two vertical walls are kept adiabatic. Three cases were investigated: square cavity without block (WB), with cold block (CB), and with hot block (HB). The nonlinear governing equations and boundary conditions are discretized using finite volume approach with the Quick scheme and solved numerically by projection algorithm for the pressure-velocity coupling together with the multigrid solver. Simulations were carried out based on various flow-governing parameters such as Hartmann number (0<Ha<45), nanoparticle volume fraction (0<<12%) and for the t...
International Journal of Numerical Methods for Heat & Fluid Flow
Purpose This study aims to analyze entropy generation and magnetohydrodynamic (MHD) natural conve... more Purpose This study aims to analyze entropy generation and magnetohydrodynamic (MHD) natural convection of hybrid nanofluid in a square cavity, with a heated elliptical block placed at the center, in presence of a periodic-variable magnetic field. Design/methodology/approach In this paper, simulations were performed with a FORTRAN home code. The numerical methodology used to solve Navier–Stokes, energy and entropy generation equations with corresponding boundary conditions, is essentially based on the finite volume method and full multigrid acceleration. Findings The cavity is filled with Ag–Tio2/Water hybrid nanofluid. The main objective of this investigation is to predict the effects of body’s size (6 cases), type of applied magnetic field (variable or uniform), the non-dimensional period number of the variable magnetic field (VMF) (0.2 ≤ Λ ≤ 0.8), the inclination angle of the VMF (0 ≤ χ ≤ 90), Rayleigh number (5 × 103 ≤ Ra ≥ 105) and Hartmann number (5 ≤ Ha ≥ 100) on thermal perfo...
Particulate Science and Technology, May 16, 2018
ABSTRACT Numerical unsteady natural convection flow in a square cavity in the presence of uniform... more ABSTRACT Numerical unsteady natural convection flow in a square cavity in the presence of uniform magnetic field is investigated. The cavity is filled with CNT-water nanofluid and heated from below with sinusoidal temperature distribution. This study has been conducted for the certain pertinent parameters of Rayleigh number Ra, Hartmann number Ha and the CNT volume fraction from Φ = 0 to 0.12. The results indicate, that for large values of Ha, increasing Φ results in an increase of the normalized average Nusselt number. The rate corresponding to CNT- volume fraction nanoparticles of 10% ensures an enhancement about 50% of the heat transfer rate compared to the standard case. The flow undergoes a period bifurcation at a Rayleigh number beyond the value 106. A critical Rayleigh number Rac of 1.077 × 106 is then computed. Finally, a correlation giving the average Nusselt number as a function of the frequency of the periodic regime is established.
Journal of Thermal Science and Technology, 2018
Paper No.17-00587 © 2018 The Japan Society of Mechanical Engineers [DOI: 10.1299/jtst.2018jtst001... more Paper No.17-00587 © 2018 The Japan Society of Mechanical Engineers [DOI: 10.1299/jtst.2018jtst0019] Abstract In this paper, heat transfer and entropy generation of MHD natural convection of Carbone NanoTube (CNT)water nanofluids in a square cavity with and without isothermal block are numerically studied. The cavity is heated sinusoidally, according to the X coordinate, from below and it is cooled isothermally from the top. The two vertical walls are kept adiabatic. Three cases were investigated: square cavity without block (WB), with cold block (CB), and with hot block (HB). The nonlinear governing equations and boundary conditions are discretized using finite volume approach with the Quick scheme and solved numerically by projection algorithm for the pressure-velocity coupling together with the multigrid solver. Simulations were carried out based on various flow-governing parameters such as Hartmann number (0<Ha<45), nanoparticle volume fraction (0<<12%) and for the t...
International Journal of Numerical Methods for Heat & Fluid Flow
Purpose This study aims to analyze entropy generation and magnetohydrodynamic (MHD) natural conve... more Purpose This study aims to analyze entropy generation and magnetohydrodynamic (MHD) natural convection of hybrid nanofluid in a square cavity, with a heated elliptical block placed at the center, in presence of a periodic-variable magnetic field. Design/methodology/approach In this paper, simulations were performed with a FORTRAN home code. The numerical methodology used to solve Navier–Stokes, energy and entropy generation equations with corresponding boundary conditions, is essentially based on the finite volume method and full multigrid acceleration. Findings The cavity is filled with Ag–Tio2/Water hybrid nanofluid. The main objective of this investigation is to predict the effects of body’s size (6 cases), type of applied magnetic field (variable or uniform), the non-dimensional period number of the variable magnetic field (VMF) (0.2 ≤ Λ ≤ 0.8), the inclination angle of the VMF (0 ≤ χ ≤ 90), Rayleigh number (5 × 103 ≤ Ra ≥ 105) and Hartmann number (5 ≤ Ha ≥ 100) on thermal perfo...