Browsing by Author "Maatki C."

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    Coupled Effects of Using Magnetic Field, Rotation and Wavy Porous Layer on the Forced Convection of Hybrid Nanoliquid Flow over 3D-Backward Facing Step
    (MDPI, 2022) Ghachem K.; Selimefendigil F.; Alshammari B.M.; Maatki C.; Kolsi L.
    In the present study, the effects of using a corrugated porous layer on the forced convection of a hybrid nanofluid flow over a 3D backward facing step are analyzed under the coupled effects of magnetic field and surface rotation. The thermal analysis is conducted for different values of the Reynolds number (Re between 100 and 500), the rotational Reynolds number (Rew between 0 and 2000), the Hartmann number (Ha between 0 and 15), the permeability of the porous layer (the Darcy number, Da between (Formula presented.) and (Formula presented.)) and the amplitude (ax between 0.01 ap and 0.7 ap) and wave number (N between 1 and 16) of the porous layer corrugation. When rotations are activated, the average Nusselt number (Nu) and pressure coefficient values rise, while the increment of the latter is less. The increment in the average Nu is higher for the case with a higher permeability of the layer. When the corrugation amplitude and wave number are increased, favorable impacts of the average Nu are observed, but at the same time pressure coefficients are increased. Successful thermal performance estimations are made by using a neural-based modeling approach with a four input-two output system. © 2022 by the authors.
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    CFD Study of MHD and Elastic Wall Effects on the Nanofluid Convection Inside a Ventilated Cavity Including Perforated Porous Object
    (MDPI, 2023) Kolsi L.; Selimefendigil F.; Omri M.; Rmili H.; Ayadi B.; Maatki C.; Alshammari B.M.
    Cost-effective, lightweight design alternatives for the thermal management of heat transfer equipment are required. In this study, porous plate and perforated-porous plates are used for nanoliquid convection control in a flexible-walled vented cavity system under uniform magnetic field effects. The finite element technique is employed with the arbitrary Lagrangian–Eulerian (ALE) method. The numerical study is performed for different values of Reynolds number ((Formula presented.)), Hartmann number ((Formula presented.)), Cauchy number ((Formula presented.)) and Darcy number ((Formula presented.)). At Re = 600, the average Nusselt number (Nu) is 6.3% higher by using a perforated porous plate in a cavity when compared to a cavity without a plate, and it is 11.2% lower at Re = 1000. At the highest magnetic field strength, increment amounts of Nu are in the range of 25.4–29.6% by considering the usage of plates. An elastic inclined wall provides higher Nu, while thermal performance improvements in the range of 3.6–6% are achieved when varying the elastic modulus of the wall. When using a perforated porous plate and increasing its permeability, 22.8% increments of average Nu are obtained. A vented cavity without a plate and elastic wall provides the highest thermal performance in the absence of a magnetic field, while using a porous plate with an elastic wall results in higher Nu when a magnetic field is used. © 2023 by the authors.
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    Ternary nanofluid cooling of an elastic plate by using double sinusoidal wavy channels under different magnetic fields
    (Springer Science and Business Media Deutschland GmbH, 2024) Selimefendigil F.; Hadrich B.; Kriaa K.; Maatki C.; Kolsi L.
    A novel cooling system for a hot elastic plate is considered by combined utilization of magnetic field, wavy channels and ternary nanofluid. Some applications can be found in electronic cooling, material processing and convective heat transfer control. The elastic object is placed between sinusoidal wavy channels where magnetic field of different strengths is imposed. Ternary nanofluid is used as cooling medium in both channels. Cooling performance assessment is made by various values of Reynolds number (Re, between 250 and 1000), Hartmann number of different channels (Ha, between 0 and 15), amplitude (A, between 0.05 and 0.3) and wave number (N, between 1 and 4) of corrugation, and nanoparticle loading (svf between 0 and 0.03). Entropy generation analysis is also considered. Thermal performance enhancement factor for the maximum and lowest Re configurations in the rigid and elastic object cases are 1.70 and 1.65, respectively. The amount of cooling performance improvement generated by imposing magnetic field at the highest strength is 58.5% and 80% with rigid and elastic objects, respectively. The cooling performance is improved by the wavy form amplitude; however, the wave number relation is non-monotonic. When comparing the wavy channel with the flat one, the increments of thermal performance for stiff and elastic plates are 52% and 57%. Using elastic and stiff objects with nanofluid results in increases in cooling performance of 47.2% and 55.5% when compared to the use of base fluid alone. The best thermal performance is always provided by a rigid item with wavy channels. The least amount of cooling is achieved by using an elastic plate and flat channel. The best options are to increase the magnetic field strength and amplitude of the wavy channel as thermal performance improves and entropy generation drops. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
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    A review study on the direct absorption solar collectors working with nanofluids
    (Springer Science and Business Media B.V., 2024) Hussain M.; Ullah S.; Alshammari S.; Selimefendigil F.; Maatki C.; Khan S.U.; Kolsi L.
    This review article focuses on the impact of working fluid characteristics, geometrical parameters and the operating coefficients in thermal efficiencies of direct absorption solar collectors (DASCs). Regarding working fluid parameters, the review emphasized the importance of type of base fluid, nanoparticle properties, such as material, size, concentration and shape. Geometrical parameters, including the collector area, aspect ratio, tube diameter and collector panel design, were identified as crucial design considerations for maximizing DASC efficiency. Additionally, the review highlighted the significance of various operating parameters. Solar irradiance was identified as a critical factor, emphasizing the importance of optimizing the collector's orientation and tilt angle to maximize solar exposure. The fluid flow rate within DASCs was also recognized as a key parameter influencing heat transfer and overall performance. Increasing the thermal flow measurement of nanomaterials has been predicted to improve the heat transfer, ultimately leading to improved thermal efficiency. By carefully considering and optimizing these parameters, it is possible to maximize the efficiency and effectiveness of DASCs, thereby advancing the utilization of solar energy for sustainable and renewable power generation. © Akadémiai Kiadó, Budapest, Hungary 2024.