Nanofluid flow over a flat surface induced by stream wise pressure gradient utilizing different mathematical models

Abstract

This thesis is concerned with the formation of boundary layer near a flat plate/wedge placed in water-based nanofluids. In model development, partial slip assumption is employed which results in the Robin–type condition in longitudinal velocity component. The resulting heat transfer process with a prescribed surface temperature is also formulated and analysed using thermal slip condition. In this thesis, two well-known theoretical models namely (i) Tiwari and Das model and (ii) Buongiorno model are applied. Firstly, buoyancy assisted or opposed Falkner-Skan flow over a heated static wedge using Tiwari and Das model is formulated. Here, nanoparticle working fluid is assumed to be water based and it contains different nanoparticle materials. The governing problem is transformed in to a coupled self-similar boundary value problem whose numerical solution is developed by MATLAB package based on the collocation approach. Numerical simulations for velocity and temperature fields are scrutinized for full ranges of solid volume fraction and pressure gradient parameter under both assisting and opposing scenarios. A comparative analysis of wall shear and heat transfer rate is conducted for different nanoparticle materials. The computational results clearly demonstrate that nanofluid assumption is indeed vital for thermal conductivity enhancement of convectional heat transfer fluids. Secondly, Buongiorno’s formulation is invoked to model nanofluid transport phenomenon over a flat plate at zero incidence, when a prescribed free stream velocity is considered. Here the unconventional condition of nanoparticle mass flux is treated. Also, variation of diffusion coefficients with temperature is retained and it is concluded that Brownian and thermophoresis diffusions have no effects on the thermal heat transfer.