Magnetohydrodynamic (MHD) Convective Nanofluid Flow, Heat Transfer and Irreversibility Analysis in a Horizontal Micro Tall Cavity with Heat Sources in the Slip Regime

摘要

The contemporary study aims to numerically analyze the MHD convective heat transfer and entropy generation analysis for the case of a micro open tall cavity filled with Al_2O_3/water under the effect of uniform magnetic field in the slip flow regime using the LBM for resolving the governing equations. The slip velocity and the temperature jump conditions are used to incorporate the micro aspect. The Brownian motion effects are considered in the thermal conductivity. The flow pattern and heat transfer characteristics and the irreversibility are studied dependently on various dimensionless independent variables such as: nanoparticles volume fraction φ(0-4%), Rayleigh number (Ra) (10~2-10~4), Knudsen number (Kn) (0-10~(-1)) and Hartmann number (Ha) (0-75). It is found that the change of aspect ratio, Ra, φ and the magnetic field strength affect the hydrodynamic and thermal behaviors inside the micro medium. Concerning the Kn, which presents the most influential parameter on the heat transfer, flow pattern, thermal field and entropy generation, it was concluded it decreases the heat transfer, entropy generation and Bejan number inside the micro tall open cavity. Moreover, it deteriorates the formed rolling cells and the plumes in the micro domain. The nanoparticles size effect is also studied, and found to reduce the heat transfer.