Finding

Paper

Abstract

A mathematical study is described to examine the concurrent influence of thermal radiation and thermal wall slip on the dissipative magnetohydrodynamic electro-osmotic peristaltic propulsion of a viscous nano-liquid in an asymmetric microchannel under the action of an axial electric field and transverse magnetic field. Convective boundary conditions are incorporated in the model and the case of forced convection is studied i.e. thermal and species (nanoparticle volume fraction) buoyancy forces neglected. The heat source and sink effects are also included and the diffusion flux approximation is employed for radiative heat transfer. The transport model comprises the continuity, momentum, energy, nanoparticle volume fraction and electric potential equations with appropriate boundary conditions. These are simplified by negating the inertial forces and invoking the Debye–Huckel linearization. The resulting governing equations are reduced into a system of non-dimensional simultaneous ordinary differential equations, which is solved analytically. Numerical evaluation is conducted with symbolic software (MATLAB). The impact of different control parameters (Hartmann number, electroosmosis parameter, slip parameter, Helmholtz-Smoluchowski velocity, Biot numbers, Brinkman number, thermal radiation and Prandtl number) on the heat, mass and momentum characteristics (velocity, temperature, Nusselt number etc.) are presented graphically. Increasing Brinkman number is found to elevate temperature magnitudes. For positive Helmholtz-Smoluchowski velocity (reverse axial electrical field) temperature is strongly reduced whereas for negative Helmholtz-Smoluchowski velocity (aligned axial electrical field) it is significantly elevated. With increasing thermal slip nanoparticle volume fraction is also increased. Heat source elevates temperatures whereas heat sink depresses them, across the micro-channel span. Conversely, heat sink elevates nano-particle volume fraction whereas heat source decreases it. Increasing Hartmann (magnetic) parameter and Prandtl number enhance the nano-particle volume fraction. Furthermore, with increasing radiation parameter the Nusselt number is reduced at the extremities of the micro-channel whereas it is elevated at intermediate distances. The results reported provide a good insight into biomimetic energy systems exploiting electromagnetics and nanotechnology and furthermore they furnish a useful benchmark for experimental and more advanced computational multi-physics simulations.

Authors

J. Prakash, E. P. Siva, D. Tripathi

Journal

Heat Transfer-Asian Research

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