Browsing by Author "Olayemi, Olalekan Adebayo"

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    Computational study of Cattaneo–Christov heat flux on cylindrical surfaces using CNT hybrid nanofluids: a solar-powered ship implementation
    (Elsevier, 2023-04-07) Obalalu, Adebowale Martins; Salawu, S. O.; Asif Memon, M.; Olayemi, Olalekan Adebayo; Ali, Mohamed R.; Sadat, R.; Odetunde, Christopher Bode; Ajala, Olusegun Adebayo; Akindele, A. O.
    This study examines the potential of using nanofluids in solar thermal energy systems. Nanofluids are known to exhibit high convection heat transfer coefficients, low specific heat, and density, making them ideal for improving the performance of solar thermal energy systems. However, this computational study investigates the application of Cattaneo-Christov heat flux on cylindrical surfaces using carbon nanotube (CNT) hybrid nanofluids, for use in a solar-powered ship. The work utilizes numerical simulations to analyze the heat transfer and fluid flow characteristics of the hybrid nanofluids. The research examines the use of single-walled and multi-walled carbon nanotubes (SWCNT and MWCNT) in engine oil (EO) as the working fluid. The Galerkin weighted residual method (GWRM) is utilized to solve the ordinary differential equations (ODEs) governing the system. The impact of various parameters, such as Cattaneo-Christov heat flux, solar thermal radiation, nonlinear stretching surface, slippery velocity, and porous media on the velocity equation, energy equation, and entropy generation are investigated and elaborated through detailed plots. The findings show that the MWCNT-SWCNT/EO hybrid nanofluid (HNF) exhibits maximum efficiency of around 2.4%, while the minimum efficiency is at 2.7%. This research provides valuable insights into the design and optimization of solar thermal systems for sustainable transportation.
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    Enhancing heat transfer in solar-powered ships: a study on hybrid nanofluids with carbon nanotubes and their application in parabolic trough solar collectors with electromagnetic controls
    (Springer Nature, 2023-06-10) Obalalu, Adebowale Martins; Asif Memon, M.; Olayemi, Olalekan Adebayo; Olilima, J.; Fenta, Amsalu
    The aim of this research is to explore the use of solar-powered ships (SPS) as a means to reduce greenhouse gas emissions and fossil fuel dependency in the maritime industry. The study focuses on improving the heat transfer efficiency in SPS by employing hybrid nanofluids (HNF) containing carbon nanotubes (CNTs). Additionally, a novel approach utilizing renewable energy and electromagnetic control is proposed to enhance the performance of SPS. The research implements the non-Newtonian Maxwell type and Cattaneo–Christov heat flux model in parabolic trough solar collectors used for ships. The study conducts theoretical experiments and simulations to evaluate the thermal conductivity and viscosity of the CNT-based HNF. Various properties, including solar thermal radiation, viscous dissipation, slippery velocity, and porous media, are assessed to determine the effectiveness of thermal transport in SPS. The research employs similarity variables to simplify the complex partial differential equations into ordinary differential equations and solves them using the Chebyshev collocation spectral method. The results indicate that the MWCNT-SWCNT/EO hybrid nanofluid significantly improves the thermal conductivity, thereby enhancing heat transfer. The HNF exhibits an efficiency rate of approximately 1.78% with a minimum efficiency rate of 2.26%.
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    Heat transfer enhancement of magnetized nanofluid flow due to a stretchable rotating disk with variable thermophysical properties effects
    (Springer, 2022-03-25) Olayemi, Olalekan Adebayo; Obalalu, Adebowale Martins; Odetunde, Christopher Bode; Ajala, Olusegun Adebayo
    Ferrofluid is a one-of-a-kind substance that functions both as a magnetic solid and as a liquid. In this article, water-based Fe3O4 and Mn–ZnFe2O4 nanofluids between parallel stretchable spinning discs are considered. To carry out the study, the influence of rotational viscosity in the flow, which is due to the difference in rotation between the fluid and magnetic particles, and the applied magnetic field are examined. Additional impacts incorporated to the novelty of the model are the variable viscosity and variable thermal conductivity. The Legendre-based collocation method is used to solve the set of governing equations. To ensure the code validity, a comparison with analytical results is conducted and an excellent consensus is accomplished. Comparisons of the pertinent parameters on the flow profiles are displayed in tabular and graphical forms. Analyses reveal that the ferromagnetic Fe3O4 nanofluid shows higher thermal conductivity strength than the ferromagnetic Mn–ZnFe2O4 nanoparticles. This study finds its usefulness in aerospace, biotechnology, medical sciences, material sciences, and so on.
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    Magnetoconvection around an elliptic cylinder placed in a lid-driven square enclosure subjected to internal heat generation or absorption
    (Wiley, 2022-04-01) Olayemi, Olalekan Adebayo; Al-Farhany, Khaled; Obalalu, Adebowale Martins; Ajide, Tomisin F.; Adebayo, Kehinde R.
    The impacts of MHD and heat generation/absorption on lid-driven convective fluid flow occasioned by a lid-driven square enclosure housing an elliptic cylinder have been investigated numerically. The elliptic cylinder and the horizontal enclosure boundaries were insulated and the left vertical lid-driven wall was experienced at a fixed hot temperature, and the right wall was exposed to a fixed cold temperature. COMSOL Multiphysics 5.6 software was used to resolve the nondimensional equations governing flow physics. A set of parameters, such as Hartmann number ( 0≤𝐻𝑎≤50 ), Reynolds number ( 10^2≤𝑅𝑒≤10^3 ), Grashof number ( 10^2≤𝐺𝑟≤10^5 ), heat generation-absorption parameter ( −3≤𝐽≤3 ), and elliptical cylinder aspect ratio (AR) ( 1.0≤𝐴𝑅≤3.0 ) have been investigated. The current study discovered that for low Reynolds number, the adiabatic cylinder AR of 2.0 provided the optimum heat transfer enhancement for the model investigated, also the impact of cylinder size diminishes beyond Gr = 10^4. But for high Reynolds (Re = 1000), the size of the cylinder with AR = 3.0 offered the highest heat transfer augmentation. The clockwise flow circulation reduces because of an increase in AR, which hinders the flow circulation. In addition, heat absorption supports heat transfer augmentation while heat generation can suppress heat transfer improvement.