Numerical investigation on transient third-grade magnetized nanofluid flow and radiative convection heat transfer from a stationary/moving cylinder: nanomaterial and nanoparticle shape effects

Abstract

In this study, a mathematical model is developed for analyzing the time-dependent magnetoconvective flow and heat transfer characteristics of an electrically conducting (functional) thirdgrade Reiner-Rivlin non-Newtonian nanofluid from a moving or stationary hot cylinder in the presence of magnetic field and thermal radiation. A well-tested convergent Crank-Nicolson type finite difference algorithm is employed to solve the transformed, nonlinear boundary value problem. The Tiwari-Das nanofluid volume fraction model is adopted for nanoscale effects and the Rosseland algebraic flux model for radiative heat flux effects. It has been shown that the shape of nanoparticles remarkably contributes to the enhancement of heat transfer. Several metallic nanoparticle types such as Al2O3, Cu, and TiO2 are examined. It is found from the investigation that the viscoelastic nanofluid with TiO2 nanoparticles results in more heat transfer than the other nanoparticles. Lower velocity and higher temperature values are computed at transient conditions with a higher third-grade fluid parameter for the flow of nanofluid (Al2O3-SA). The plots of transient friction and heat transfer coefficients are visualized at the surface of a hot cylinder. The tabulated heat transfer coefficient is comparatively more for the moving cylinder than the stationary cylinder. Detailed validation of results of the numerical scheme with previous studies is included. The simulations find applications in coating deposition (enrobing) of magnetic nanomaterial at high temperatures, functional nanomaterial synthesis, etc.