Interacting influences of Lorentz force and bleeding on the hydrothermal behaviors of nanofluid flow in a trapezoidal recess with the second law of thermodynamics analysis

摘要

This study deals with the analysis of the interacting influences of Lorentz force and bleeding on the hydrothermal behaviors of magnetohydrodynamic (MHD) nanofluid flow and entropy generation in a trapezoidal recess. This trapezoidal recess is created by two inclined steps in a horizontal channel. The Lorentz force is appeared due to the existence of a magnetic field in the flow domain. The Brownian motion influences on the effective characteristics of CuO -water nanofluid are considered to have more accuracy. The effects of bleeding coefficients (- 0.005 ≤V_w ≤ + 0.005), Hartmann number (0 ≤ Ha ≤ 60) and concentration of solid nanoparticles (0≤φ≤ 0.04) on the flow characteristics, heat transfer and flow irreversibility rates are investigated. The results show that the trends and values of friction coefficient, Nusselt number and entropy generation number can be different at the various magnitudes of Ha and V_w, whereas the φ parameter only increases the values of them. These differences are related to the variations of streamlines contours against the Ha, V_w and φ parameters.