Hydrodynamic analysis of the nanofluids flow in a microchannel with hydrophobic and superhydrophobic surfaces

We studied the hydrodynamic features of the nanofluids flowing inside a straight microchannel with hydrophilic, hydrophobic, and superhydrophobic walls by the finite volume method. The single-phase method is applied for the prediction of hydrodynamic properties of water/Al2O3 nanofluids. The nanofluid is based on deionized water with particle concentrations of 0.1%, 0.5%, and 1.0%. Interpretations for velocity profiles, Poiseuille number, pumping power, and friction coefficients are presented for different hydrophobicities of the walls. We considered various flows with Reynolds numbers in the range of 50 to 400 and constant heat flux of 10,000 W/m2. The obtained results depict that the implementation of nanofluids leads to increase pumping power which is greater for higher volume fractions. The Poiseuille number shows that the effects of the entry region decrease when the superhydrophobic walls are applied because of the reduction in velocity slopes at the wall. For hydrophilic walls, nanofluid increases the pumping power by 74%. However, superhydrophobic walls with the nanofluid flow cause a 47% decrease in pumping power compared to the water flow with the usual walls. Using the superhydrophobic wall with nanofluids resolves the disadvantages of pressure drop rises significantly. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.