Minimization of entropy production in the transient thermocapillary flow of Al₂O₃-Cu hybrid nanoliquid film over a disk

This research article intends to investigate the entropy generation in the context of unsteady thermocapillary convection of a hybrid nanoliquid thin film over a disk within magnetohydrodynamic considerations. A set of partial differential equations using Prandtl's boundary layer theory has been written to present the flow situation in mathematical form. Irreversible processes of viscous and Joule dissipations have been considered in the temperature balance equation. A suitable choice of transform variables facilitate a system of ODEs from original PDEs representing the flow phenomena. This system of ODEs is solved by shooting technique in conjunction with Runge-Kutta 4th-order numerical scheme. The physical observations for velocity, temperature and quantities of engineering quantities are well presented using graphs and tables. One of the significant results of this study shows that with the use of blade shaped nanoparticles of both kind, maximum heat transfer at the disk surface is achieved and it is least when spherical shaped nanoparticles are used. (author)