Mathematical Modelling and Parametric Analysis of Nanofluid Flows Induced by Rotating Disks

Abstract

This thesis thoroughly analyzes heat transfer in copper-water nanofluid flows induced by disk rotation. It considers various variables, including nanoparticle concentration, Hall currents, Ohmic heating, magnetic flux, and heat generation/absorption. The study employs numerical methods, including the shooting method, similarity transformations, and mathematical modeling. Initially, it develops a steady flow model for a nanofluid produced by a rotating circular disk in a porous medium and explores the effects of Hall currents and Ohmic heating on flow variables, revealing a direct proportion between axial velocity and nanoparticle volume percentage. The research also investigates heat transfer rates in hybrid nanofluid flows generated by the rotation of a spherical porous disk, considering Hall currents, Ohmic heating, heat generation/absorption, and magnetic flux. The study identifies the importance of wall suction in shaping velocity components, where higher Hartman numbers lead to increased radial and reduced axial velocities. It recommends considering different models for apparent viscosity, thermal conductivity of nanofluids, and the impact of external magnetic flux. The subsequent analysis of a hybrid nanofluid under a constant magnetic field reveals that higher nanoparticle concentrations boost convective heat transfer while lowering local skin friction coefficients. Heat generation/ absorption and thermal radiation significantly influence heat transfer, with increased thermal conductivity and radiation parameters resulting in higher temperature and Nusselt number. Additionally, the research on copper-water nanofluid flows through a porous medium account for velocity and temperature slip conditions, along with heat generation/ absorption, showcasing how the nanoparticle volume fraction and the presence of a heat source/sink affect nanofluid temperature. The study also emphasizes the substantial influence of velocity slip parameters on velocity components, with disk surface polishing facilitating slip and reducing stresses. Generally, the findings provide insights into the influence of various parameters and conditions, which have practical implications in fields such as energy engineering and thermal management.