Search

In this paper, we focus on the two-dimensional pulsating nanofluid flow through a parallel-plate channel in the presence of a magnetic field. The pulsating flow is produced by an applied pressure gradient that fluctuates with a small amplitude. A kind of proper transformation is used so that the governing equations describing the momentum and thermal energy are reduced to a set of non-dimensional equations. The analytical expressions of the pulsating velocity, temperature, and Nusselt number of nanofluids are obtained by the perturbation technique. In the present study, the effects of the Cu-H2O and Al2O3-H2O nanofluids on the flow and heat transfer in pulsating flow are compared and analyzed. The results show that the convective heat transfer effect of Cu-H2O nanofluids is better than that of Al2O3-H2O nanofluids. Also, the effects of the Hartmann number and pulsation amplitude on the velocity, temperature, and Nusselt number are examined and discussed in detail. The present work indicates that increasing the Hartmann number and pulsation amplitude can enhance the heat transfer of the pulsating flow. In addition, selecting an optimal pulsation frequency can maximize the convective heat transfer of the pulsating flow. Therefore, improved understanding of these fundamental mechanisms is conducive to the optimal design of thermal systems. [ABSTRACT FROM AUTHOR]

The influence of stress jump conditions on a steady, fully developed two-layer magnetohydrodynamic electro-osmotic nanofluid in the microchannel, is investigated numerically. A nanofluid is partially filled into the microchannel, while a porous medium, saturated with nanofluid, is immersed into the other half of the microchannel. The Brinkmann-extended Darcy equation is used to effectively explain the nanofluid flow in the porous region. In both regions, electric double layers are examined, whereas at the interface, Ochoa-Tapia and Whitaker's stress jump condition is considered. The non-dimensional velocity, temperature, and volume fraction of the nanoparticle profiles are examined, by varying physical parameters. Additionally, the Darcy number, as well as the coefficient in the stress jump condition, are investigated for their profound effect on skin friction and Nusselt number. It is concluded that, taking into account the change in shear stress at the interface has a significant impact on fluid flow problems. [ABSTRACT FROM AUTHOR]