Flow and Heat Transfer Characteristics of non-Newtonian Nanofluids


The aim of this thesis is to investigate the flow, heat transfer and entropy generation characteristics of thermal systems containing non-Newtonian nanofluids. Extensive research is carried out to study the flow and heat transfer characteristics of nanofluids considering different flow geometries, boundary conditions, external effects and surface motion etca. However limited attention is given towards study of non-Newtonian nanofluids. In real situation nanofluids do not have characteristics of Newtonian fluids, hence it is more appropriate to consider them as non-Newtonian fluids. Keeping above in view the present research is devoted to the study of flow, heat transfer and entropy generation of non-Newtonian nanofluid including effects of applied magnetic field, thermal radiation and variable thermophysical properties. Three non-Newtonian fluid models namely, Maxwell, PowellEyring and Casson are considered for the nanofluids. The mathematical model include electrically conducting nanofluid occupies the space over a porous stretching surface and the flow is generated due to the non-uniform stretching of the surface. The fundamental equations are obtained from the laws of conservation of mass, momentum and energy. These partial differential equations are transformed into a system of coupled nonlinear ordinary differential equations by means of suitable similarity transformation and then solved by an efficient numerical finite difference scheme known as Keller box method. The numerical results are presented in the form of graphs and tables for variation in parameters, for example, non-Newtonian parameter, material parameter, porous medium parameter, nanoparticle volume concentration parameter, velocity slip parameter, thermal radiation parameter, suction/injection parameter, Biot number, Reynolds number and Brinkman number. The impact of these parameters has been observed on the velocity, temperature and entropy generation profiles of the nanofluid.

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