The study of atomic porosity effect on water/Fe nanofluid flow in a microchannel with a molecular dynamics method

In this study, the molecular dynamics method is used to study the atomic behavior of water and water/Fe nanofluid within a microchannel. In our simulations, the microchannel walls have atomic porosity with various values. The results show that the values of density, velocity, and temperature vary by inserting atomic porosity into the microchannel. Numerically, by increasing the porosity value from 1% to 5%, the maximum densities of water and water/Fe nanofluid decrease to 0.03 atom/angstrom(3) and 0.032 atom/angstrom(3). Further, the maximum values of water and water/Fe nanofluid velocities converged to 0.038 and 0.053 angstrom/fs. The temperatures of water and water/Fe nanofluid are other parameters which reach to 535 K and 803 K by inserting the porosity into the microchannel walls. Physically, we conclude that the porosity value has an important effect on the fluid/nanofluid atomic and thermal behavior such as phase transition phenomena. Numerically, by inserting the atomic porosity into microchannel walls, the phase transition time in water/Fe nanofluid structure varies from 402,000-time steps to 282,000-time steps (Delta t = 1 fs). So, the atomic porosity improves the thermal behavior of nanofluid. (c) 2020 Elsevier B.V. All rights reserved.