Baffle and geometry effects on nanofluid forced convection over forward- and backward-facing steps channel by means of lattice Boltzmann method

摘要

In this study, we present a numerical simulation of MWCNT-Fe3O4/water hybrid nanofluid forced convection heat transfer over the forward- and backward-facing steps channel having a baffle fixed on its top wall. A FORTRAN's homemade code based the lattice Boltzmann method (LBM) is used here. The effects of the Reynolds number (25 <= Re <= 100), the volume fraction of nanoparticles (0 <= phi <= 0.003), the position of baffle (3 <= X-2 <= 7), the length of baffle (0 <= h <= 1.5) and the geometry parameter (2 <= X-1 <= 4) on flow pattern and heat transfer characteristics are provided a deep insight. The results indicate that the average Nusselt number is an increasing function of Re and phi. The baffle has a significant effect on the flow pattern and heat transfer characteristics. When the length of the baffle increases, the recirculation region behind the backward-facing step shrinks. The average Nusselt number increases by increasing the length of the baffle or moving the baffle towards the backward-facing step. (C) 2020 Elsevier B.V. All rights reserved.