MHD Steady/Unsteady Porous Boundary Layer of Cu–Water Nanofluid with Micropolar Effect over a Permeable Surface

Kamal Raslan,Elsayed Abedel-Aal,Selim Mohamadain,Mohamed Abdel-Wahed

doi:10.3390/app8050736

Kamal Raslan, Elsayed Abedel-Aal + Show 2 more

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https://doi.org/10.3390/app8050736

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Abstract

This work provides a mathematical model for the cooling process of a moving surface, in the presence of a uniform external magnetic field and thermal radiation, through a porous medium by using a weak concentration micropolar nanofluid. The model—based on the conservation equations of the unsteady case in the momentum and thermal boundary layer—takes into consideration the effect of the suction process. The conservation equations were transformed into ordinary differential equations using similar transformation techniques. The equations were solved numerically for the general case and analytically for the steady case. The rate of heat transfer, couple shear stress, and surface shear stress are deduced. We discuss the impact of these physical characteristics on the mechanical properties of the surface that will be cooled.

Highlights

We enhanced the thermal conductivity of the coolant based on its essential effects on many engineering applications, such as the heat treatment of metals [1]
We studied the magnetohydrodynamics (MHD) free convection of Al2 o3 –water nanofluid by considering the thermal radiation problem [5]
It is useful to mention the final quality of the surface that is controlled by the surface shear stress and couple stress

Summary

Introduction

We enhanced the thermal conductivity of the coolant based on its essential effects on many engineering applications, such as the heat treatment of metals [1]. Creating more useful metals is one of the most important aims of researchers In this process, the metal is heated to a certain temperature and cooled in a series of specific operations. Nanofluids have properties that make them useful in many heat transfer applications, such as microelectronics, fuel cells, pharmaceutical processes, hybrid powered engines, engine cooling/vehicle thermal management, domestic refrigerators, heat exchangers, and the reduction of flue gas temperature in boilers [2]. In 1995, the authors of [3] proposed the idea of enhancing the thermal conductivity of the fluids using these nanoparticles This was the first push for researchers to conduct studies that investigated the effects of nanoparticle types, sizes, and concentrations on the heat transfer characteristics and took into consideration some of the effects such as the thermal radiation, variable heat flux, magnetic field, and suction/injection processes [4]. We studied the magnetohydrodynamics (MHD) free convection of Al2 o3 –water nanofluid by considering the thermal radiation problem [5]

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