Insight into the addition of multi-walled carbon nanotubes to dynamics of water conveying single surface carbon nanotubes due to torsional motion of cylinder subject to Lorentz force and joule heating

Abstract

Hybrid nanofluid is deployed to optimize the heat transfer features of an axisymmetric magnetohydrodynamic (MHD) flow exterior to a rotating cylinder. Hybrid nanofluids contain composite nanoparticles, which improve thermal conductivity. Here, two distinct particles single and multi-walled carbon nanotubes (CNTs) are taken and mixed to form hybrid nanoparticles, and water is taken as the working fluid. The energy transport phenomenon is examined by incorporating the Joule heating effect. The axial pressure gradient is generated as a consequence of the torsional motion of the cylinder, which results in the wall jet phenomenon on the axial axis. The governing equations are transformed into an ordinary differential system in view of the similarity group. The numerical approach bvp4c is employed to solve the problem. The graphical results for flow and thermal energy transport with a comparison of nanofluid and hybrid nanofluid are analyzed. The axial component of velocity escalates by augmenting Reynolds number, while the azimuthal components of velocity and thermal profile decline. Moreover, the numerical outcomes of wall stresses and Nusselt number enhance for higher Reynolds number. The temperature field declines by increasing the Prandtl number because of less thermal diffusivity.