A Study of Generalized Vortex Flow and Heat Transfer Involving Nanofluids

Abstract

In this thesis, a nanofluid boundary layer that develops above a plane permeable surface is analysed numerically. The focus of this thesis is twofold. Firstly, to investigate the generalized vortex flow in a 𝐶𝑢 − 𝐴𝑙2𝑂3/water-based hybrid nanofluid subjected to viscous dissipation effects using Tiwari and Das model. Secondly, to examine a two-phase Buongiorno mathematical model for a generalized vortex flow. In present work, vortex motion is characterized by a prescribed tangential flow with velocity proportional to 𝑟𝑚, where 𝑟 is radial coordinate and 𝑚 denotes the power-law index. Simulations are made by assuming a powerlaw surface temperature distribution. Different from previously adopted practice, the diffusion coefficients are not assumed constant here. A similarity solution is proposed, which transforms the constitutive equations into a coupled differential system whose solution is evaluated numerically by MATLAB function bvp4c. Results display a considerable expansion in thermal boundary layer whenever nanoparticles are present. Important quantities like normalized wall shear, disk cooling rate and entrained flow are scrutinized for varying choices of parameters. The contribution of Brownian diffusion and Soret effect on the vortex induced motion is studied. The graphical and tabular results demonstrate that these parameters provide a remarkable enhancement in the heat and mass transfer rate.