Maghetohydrodynamic flows of micro/nano fluids through thin capillaries

Abstract

Steady magnetohydrodynamic (MHD) flows of suspensions of conducting micro/nanoparticles through a thin tube of a circular cross-section in a transverse constant magnetic field driven by a constant pressure drops at the ends of the tube is studied. The governing MHD system of equations for a viscous incompressible micro/nanofluid in the non-induction approximation is solved with the second order velocity slip boundary condition at the wall of the tube. The material parameters of the fluid are considered as nonlinear functions of the particle concentration according to the mixture models of suspensions and electric conductivity theory. The velocity field, pressure, electric current and magnetic field have been computed as series expansions. The influence of two non-dimensional slip coefficients of the flow rate and wall shear stress is studied. Optimal concentrations of the micro/nanoparticles in the suspensions have been computed from the minimum entropy production condition for different slip conditions, material parameters, magnetic fields and flow regimes (Reynolds and Hartmann numbers).