Entropy Analysis of Nanofluid flow in a Fluidized Bed Dryer in Presence of Induced Magnetic Field

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Kiptum J. Purity, Mathew N. Kinyanjui, Edward R. Onyango


The study investigates generation of entropy in an unsteady, incompressible nanofluid flow occurring within a fluidized bed dryer used in tea processing industries. The study considered the presence of variable magnetic field, influence of viscous dissipation, thermal radiation and chemical reaction. The nonlinear partial differential equations of momentum, energy and concentration were derived. A finite difference numerical scheme was employed to obtain an approximate solution for the nonlinear partial differential equations governing the flow. Entropy generation is then determined from velocity, concentration and temperature profiles obtained from solution of momentum, mass and energy equations. The study illustrated the impact of various flow parameters on entropy generation and Bejan number through graphical presentations while numerical values for skin friction coefficient, heat and mass transfer rates were provided in tabular form. Study of entropy generation allows one identify factors which contribute to energy inefficiencies in a thermal system and allows different stakeholders or designers of bed dryers in tea factories identify ways of improving the dryer or designing more effective dryers. Bejan number is used in thermodynamics to evaluate efficiency of thermal systems such as fluidized bed dryers. It helps one design heat exchangers which maximizes heat transfer while minimizing energy losses. The findings of this study are essential in improving the performance, efficiency and the design of a fluidized bed dryer involving heat and mass transfer as well as fluid flow.

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