Influence of variable viscosity and thermal conductivity, hydrodynamic, and thermal slips on magnetohydrodynamic micropolar flow: A numerical study

Abstract

Thermophysical and wall-slip effects arise in many areas of nuclear technology. Motivated by such applications, in this article, the collective influence of variableviscosity, thermal conductivity, velocity and thermal slip effects on a steady two-dimensional magnetohydrodynamic micropolar fluid over a stretching sheet is analyzed numerically. The governing nonlinear partial differential equations have been converted into a system of nonlinear ordinary differential equations using suitable coordinate transformations. The numerical solutions of the problem are expressed in the form of nondimensional velocity and temperature profiles and discussed from their graphical representations. The Nachtsheim-Swigert shooting iteration technique together with the sixth-order Runge-Kutta integration scheme has been applied for the numerical solution. A comparison with the existing results has been done, and an excellent agreement is found. Further validation with the Adomian decomposition method is included for the general model. Interesting features in the heat and momentum characteristics are explored. It is found that a greater thermal slip and thermal conductivity elevate thermal boundary layer thickness. Increasing Prandtl number enhances the Nusselt number at the wall but reduces wall couple stress (microrotation gradient). Temperatures are enhanced with both the magnetic field and viscosity parameter. Increasing momentum (hydrodynamic) slip is found to accelerate the flow and elevate temperatures.boundary layers, magnetic field, micropolar fluids, nuclear thermal transport, numerical solutions, thermal slip, variable thermal conductivity, velocity slip | INTRODUCTIONHeat transfer is a fundamental aspect of many nuclear engineering transport processes. It may arise in any of the three familiar modes (conduction, convection, and radiation) and indeed these modes often arise simultaneously. Interesting applications include phase change saturated nucleation (see Uesawa et al 1 ), transient electrically conducting convection flows of liquid sodium, 2 nuclear propulsion systems cooling, 3 conjugate thermal transport, 4 supercritical thermal convection in rod bundles, 5 heat emission in turbulent flows of mercury, sodium, lead-bismuth, and sodium-potassium liquid metals, 6 and hybrid electrolysis systems exploiting nuclear energy. 7 Electromagnetic flows also arise in nuclear power systems wherein magnetic fields are deployed to control high-temperature electrically conducting plasmas from damaging, for example, channel walls. Magnetohydrodynamics (MHDs) concern the interaction between electrically conducting liquids and applied magnetic fields. It has extensive applications in emergency heat removal in fast reactors, 8 molten metal pumps for rapid removal of heat from cores, 9 and feeder wall thinning mechanisms in flow-assisted corrosion of alloys in nuclear reactor channels. 10 Although often the working fluids in nuclear reactor systems are air and water, many non-Newtonian liquids are increasingly being deployed. Such fl...

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