Thermodynamic second law analysis for a gravity-driven variable viscosity liquid film along an inclined heated plate with convective cooling

The inherent irreversibility and thermal stability in a gravity-driven temperature-dependent variable viscosity thin liquid film along an inclined heated plate with convective cooling is investigated. In this study, both the isothermal and isoflux heating of the plate are considered. The free surface of the liquid film is assumed to exchange heat with the surroundings following Newton’s cooling law and the fluid viscosity model varies as an inverse linear function of the temperature. Analytical solutions are constructed for the governing boundaryvalue problem, and important properties of velocity and temperature fields such as thermal stability criterion are obtained. Expressions for volumetric entropy generation numbers, irreversibility distribution ratio, and the Bejan number in the flow field are also obtained and discussed quantitatively.

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