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    Computational modelling and entropy generation analysis of nanofluids in a channel
    (Nelson Mandela African Institution of Science and Technology, 2016) Mkwizu, Michael H.
    Nanofluid is a fluid containing nanometre- sized particles, called nanoparticles. These fluids are engineered colloidal suspension nanoparticles in a based fluid. The commonly used fluids are water, ethylene, oil and lubricant. Entropy is an extensive thermodynamic property that is the measure of a system’s thermal energy per unit temperature that is unavailable for doing useful work. That is it destroys the available energy in any flow process and thermal system. This study consists of six chapters. Chapter one is an introduction, in this chapter useful terms have been defined, objectives of the study, statement of the problem, significance of the study ware stated. The method used for analysis in all chapters is a semi discretization finite difference method together with Runge-Kutta Fehlberg integration scheme. The nanoparticles used was Copper (Cu) and Alumina (AI2O3). In chapter two, the analysis of the entropy generation in a variable viscosity channel flow of nanofluids with convective cooling was numerically investigated. The results revelled that Entropy generation rate generally increases with time /, Eckert number Ec, viscosity variation parameter /?, pressure gradient A, thermophoresis parameter Nt. Increase in Biot Bi increase entropy generation at the walls but decreases entropy generation within the channel. The paper was prepared and published in Comptes Rendus Mecanique. In chapter three, the combined effect of buoyancy force and convective cooling on the unsteady flow, heat transfer and entropy generation rate in water based nanofluids was investigated. A^Oj-water nanofluid observed to produces higher entropy than Cu-water nanofluid. Fluid friction irreversibility dominants the channel centreline region while the effects of heat transfer irreversibility near the walls increases with Grashof number Gr, Ec, A, but decreases with nanoparticles volume fraction