Browsing by Author "Mansouri, Kacem"

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    Analytical solution of non-newtonian nanofluid flows within circular duct under convective boundary condition
    (International Information and Engineering Technology Association, 2021) Tahiri, Antar; Mansouri, Kacem; Rahmani, Kouider; Kouadri, Amar; Douroum, Embarek
    At the outset, this work aims to carried out an analytical investigation of forced convection by establishing a laminar flow into circular duct under convective boundary conditions of the third type for non-Newtonian nanofluid, the fluid containing TiO2 uniformly dispersed in aqueous solution with 0.5wt% of CMC solutions (Carboxymethyl Cellulose) is used as working fluid. The viscous dissipation effects are taken into account, the employed methodology is based on a combination of the Ritz variational approach with the Laplace transformation technique, so the power-law fluids flow model is used to describe the non-Newtonian fluid behavior. The effect of dimensionless parameters such as Biot (Bi), Brinkman (Br), Peclet (Pe) numbers, power-law index (n), and nanoparticles concentration (φ) on the temperature distribution contours and on the examined local Nusselt number. Our results have been compared with those found in the literature in particular the cases of base fluids (φ=0) with and without viscous dissipation effects
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    Application of variational formulation to the periodic conjugated laminar forced convection within ducts
    (2011) Mansouri, Kacem; Hadiouche, Ahmed; Bechiri, Mohammed
    A theoretical study of laminar forced convection with a parabolic velocity profile inside parallel-plate channels and circular ducts, subjected to a sinusoidally varying inlet temperature, is presented. Thermal diffusion in the duct wall and a boundary condition that accounts for external convection are considered. A new methodology is presented to this extended Graetz problem by using the Laplace transform with a Ritz method. The variation of the amplitudes and phase lag for the centerline, wall, and fluid bulk temperature are investigated. The wall heat flux along the channel is also determined. It is concluded that for large values of wall thermal capacitance, the thermal wave is rapidly damped along the duct and the Biot number will slightly affect the dimensionless temperature amplitude. The effects of the wall transverse conduction are more pronounced at large values of the parameter β. The results are plotted and tabulated for comparison with the literature
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    A comprehensive numerical study on melting performance in a storage cavity with partial metal foam integration: Design and economic assessment
    (Elsevier, 2024) Cheradi, Hanane; Haddad, Zoubida; Iachachene, Farida; Mansouri, Kacem; Arıcı, Müslüm
    Despite remarkable technological progress aimed at improving thermal performance of storage systems, designing cost-effective thermal storage solutions still remains a challenge. Consequently, to address this gap, the current study provides a detailed numerical analysis of the melting performance within a storage cavity with partial metal foam integration, considering both design and economic aspects. Five distinct designs were considered to provide a comprehensive assessment of the melting process including non-porous and porous designs. Various factors such as foam position, foam shape and foam filling ratio were examined under different criteria. The results revealed that designs employing kite-shaped, triangular-shaped, square-shaped, and trapezoidal-shaped foam under optimal location resulted in melting time reduction of 74.8 %, 67.0 %, 50.9 %, and 42.8 %, respectively, in comparison to the non-porous design. The findings highlight the kit-shaped foam as the optimal foam shape, with a notable 7.8 % difference in melting times between designs with kite and triangular foams, and an 8.1 % disparity between designs with square and trapezoidal foams. From an economic assessment, it was found that the kit-shaped foam filling design, with a 1/3 filling ratio, proved to be cost-effective when the unit price ratio of the metal foam to PCM fell within the range of 4 to 12. Interestingly, for ratios below 4, the same design, with a 1/2 filling ratio, emerged as an economical solution. This study contributes to the field by providing quantitative insights into the design and economic viability of metal foam integrated thermal storage systems.
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    Exact solution of thermal energy storage system using PCM flat slabs configuration
    (Elsevier, 2013) Bechiri, Mohammed; Mansouri, Kacem
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    Flows characteristics of two immiscible swirling fluids in a cylinder
    (Mechanika, 2024) Brahma, Kenza; Saci, Rachid; Mansouri, Kacem; Imoula, Malika
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    Heat transfer and entropy generation in viscous-joule heating MHD microchannels flow under asymmetric heating
    (Emerald Publishing, 2024) Tahiri, Antar; Ragueb, Haroun; Moussaoui, Mustafa; Mansouri, Kacem; Guerraiche, Djemaa; Guerraiche, Khelifa
    Purpose: This paper aims to present a numerical investigation into heat transfer and entropy generation resulting from magnetohydrodynamic laminar flow through a microchannel under asymmetric boundary conditions. Furthermore, the authors consider the effects of viscous dissipation and Joule heating. Design/methodology/approach: The finite difference method is used to obtain the numerical solution. Simulations are conducted across a broad range of Hartmann (Ha = 0 ∼ 40) and Brinkman (Br = 0.01 ∼ 1) numbers, along with various asymmetric isothermal boundaries characterized by a heating ratio denoted as ϕ. Findings: The findings indicate a significant increase in the Nusselt number with increasing Hartmann number, regardless of whether Br equals zero or not. In addition, it is demonstrated that temperature differences between the microchannel walls can lead to substantial distortions in fluid temperature distribution and heat transfer. The results reveal that the maximum entropy generation occurs at the highest values of Ha and η (a dimensionless parameter emerging from the formulation) obtained for ϕ = −1. Moreover, it is observed that local entropy generation rates are highest near the channel wall at the entrance region. Originality/value: The study provides valuable insights into the complex interactions between magnetic fields, viscous dissipation and Joule heating in microchannel flows, particularly under asymmetric heating conditions. This contributes to a better understanding of heat transfer and entropy generation in advanced microfluidic systems, which is essential for optimizing their design and performance.
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    Influence of curvature on tear film dynamics
    (Elsevier, 2017) Allouche, Moussa; Ait Abderrahmane, Hamid; Djouadi, Seddik M.; Mansouri, Kacem
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    Instability of opposing double diffusive convection in 2D boundary layer stagnation point flow
    (Elsevier, 2015) Nait Bouda, Faical; Mendil, Fatsah; Sadaoui, Djamel; Mansouri, Kacem; Amaouche, Mustapha
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    Irreversibilities and heat transfer in magnetohydrodynamic microchannel flow under differential heating
    (Elsevier, 2023) Ragueb, Haroun; Tahiri, Antar; Behnous, Dounya; Manser, Belkacem; Rachedi, Kamel; Mansouri, Kacem
    This study investigates heat transfer and entropy generation in a microchannel subjected to differential heating, viscous dissipation, and Joule heating within a magnetohydrodynamic (MHD) fluid flow. A finite difference method with a fully implicit scheme is employed to accurately model temperature distribution and entropy generation. A comparison between the average Nusselt numbers (Nu) calculated using the classical method and the Bennett Formula reveals a notable discrepancy, particularly at the entry length (up to 14%). It has been found that when one plate is heated while the other is cooled and the Hartmann number (Ha) is low, the average Nu for both plates converges to 2. However, at high Ha values considering viscous dissipation and Joule heating, there is an 8% deviation between the Nu values of the two plates, with the higher Nu found on the cooling plate. Sensitivity analyses explore the impact of control parameters on entropy generation, emphasizing the significance of η as a key parameter that reflects the system's resistance to entropy generation. Increasing η from 0.1 to 0.5 results in a 32% reduction in entropy generation. In particular, for microchannels, substantial η high values imply reduced entropy generation, highlighting their efficiency in heat transfer.
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    A numerical study of viscous dissipation effect on non-Newtonian fluid flow inside elliptical duct
    (Elsevier, 2013) Ragueb, Haroun; Mansouri, Kacem
    Laminar heat transfer inside duct with elliptical cross section, subjected to uniform wall temperature is studied by taking into account the viscous dissipation. The temperatures distributions are evaluated numerically by using a dynamic Alternating Direction Implicit method (dADI). Nusselt number (Nu) is presented graphically for various Brinkman number (Br) and aspect ratio for a non-Newtonian fluid described by the power law model. The results obtained showed a good agreement with those found in the literature for fluid flow in circular cross section ducts and in elliptical cross section without viscous dissipation effects. It is shown that in the fully developed region and for Br – 0, Nusselt number has a fixed asymptotic value independent of Brinkman number (Br). In the thermally developing region, it is observed a single fixed point independent of heating or cooling condition which the numerical value is equal to the asymptotic Nusselt number. Another relevant feature is that in the fully developed region, the Nusselt number increases with the aspect ratio
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    One-dimensional model of heat exchanging throughout a three-dimensional building room integrated by phase change material
    (Elsevier B.V., 2025) Bechiri, Mohammed; Mansouri, Kacem
    This paper presents a numerical investigation aimed at analyzing heat exchange and thermal comfort conditions within a building room during the hot season. In this setup, one wall, the roof, and the floor are thermally insulated, while the remaining three walls are constructed with brick embedded with phase change material (PCM). These non-insulated walls are subjected to a constant external surface temperature. Additionally, a latent heat storage unit comprising a set of tubes is installed in the room's ceiling region. The mathematical model employed in this study is based on pure conduction in the brick and in the walls containing PCM, as well as natural convection in the room air. Natural convection within the liquid phase of the PCM storage unit is accounted for by considering the effective thermal conductivity's dependence on the liquid fraction. The enthalpy method is utilized to solve energy equations in both the solid and liquid phases of the PCM, whether in walls or tubes. Heat transfer within the room is assumed to be unidirectional through the walls and tubes, with zero-dimensional considerations in the air region. The developed model is thoroughly analyzed and compared with existing literature, showing good agreement. Subsequently, a parametric study investigating various geometrical and thermo-physical parameters of the building room is conducted. The results indicate that the PCM within the walls contributes to maintaining indoor temperatures within the comfort range. Furthermore, the heat storage unit helps sustain indoor temperatures at the comfort level as long as the PCM within the tubes is undergoing melting processes.
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    Thermodynamic Model of a Gas Turbine Considering Atmospheric Conditions and Position of the IGVs
    (MDPI, 2024) Boushaki, Tarik; Mansouri, Kacem
    Gas turbines are widely used in power generation due to their efficiency, flexibility, and low environmental impact. Modeling, especially in thermodynamics, is crucial for the designer and operator of a gas turbine. An advanced and rigorous thermo dynamic model is essential to accurately predict the performance of a gas turbine under on-design operating conditions, off-design or failure. Such models not only improve understanding of internal processes but also optimize performance and reliability in a wide variety of operational scenarios. This article presents the development of a thermodynamic model simulating the off-design performance of a gas turbine. The mathematical relationships established in this model allow for quick calculations while requiring a limited amount of data. Only nominal data are required, and some additional data are needed to calibrate the model on the turbine under study. A key feature of this model is the development of an innovative relationship that allows direct calculation of the mass flow of air entering the turbine and, thus, the performances of the turbine according to atmospheric conditions (such as pressure, temperature, and relative humidity) and the position of the compressor inlet guide vanes (IGV). The results of the simulations, obtained using code implemented in MATLAB (R2014a), demonstrate the efficiency of the model compared to experimental data. Indeed, the model relationships exhibit high determination coefficients (R2 > 0.95) and low root mean square errors (RMSE). Specifically, the simulation results for the air mass flow rate demonstrate a very high determination coefficient (R2 = 0.9796) and a low root mean square error (RMSE = 0.0213).
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    Vortex characteristics of two rotating immiscible fluids
    (2023) Brahma, Kenza; Saci, Rachid; Mansouri, Kacem
    Hydrodynamic and behavior of laminar confined axisymmetric flows driven by the rotating top disk in cylindrical cavity have been studied numerically. The vertical cavity, is filled with two superposed immiscible incompressible fluids. The top more viscous liquid drives the lower heavier fluid via the interface shear. The study, identified and highlighted a flow topology of types of axisymmetric recirculation regions; depending upon the effects of the disk rotation rate. This work confirms partly previous experimental observations and provides additional quantitative findings; particularly in the vicinity of the interface. The findings are in good accord with the experiments and show that vortex size increases with increasing rotation rate. The basic flow is made up of two clockwise circulation cells, separated by a thin layer of anticlockwise circulation (TCL). The gap thickness of TCL decreases with increasing rotation rate however, the interface high increases as rotation rate increases