Analysis of carbon nanotubes-based nanofluid with paraffin oil in 3D MHD Darcy-Forchheimer flow through a bi-directional stretchable surface: Application to heat exchanger systems

In this paper, a three-dimensional Darcy-Forchheimer flow model is considered to investigate the flow behavior of conducting paraffin oil with carbon nanotubes. The governing partial differential equations of the model are converted into a system of ordinary differential equations by using a similarity transformation. Then, a conversion numerical method along with a shooting technique is used to obtain the solutions to the governing ordinary differential equations. The study reveals significant effects of the porosity, radiation, thermophoresis and the Brownian motion on the flow and heat transfer characteristics. Also, the influences of the physical parameters on the bi-directional velocity, temperature and fluid concentration are discussed in detail. Since carbon nanotubes have high thermal conductivity, it has a high impact on the temperature profiles. Furthermore, as the paraffin oil has well-defined thermal properties, it can be used as a fluid to augment the heat transfer. The presence of carbon nanotubes in the fluid enhanced the thermal conductivity which in turn increased the temperature of the fluid. The magnetic field reduced the bi-directional velocity of the fluid but increased the temperature due to the stimulating effect of the Lorentz force. Hence, this heat transfer study of paraffin oil with carbon nanotubes has a wide range of industrial applications to steam generation, thermal management, heat-treated material and engine cooling.