Second law analysis on EMHD with variable viscosity and thermal conductivity of hybrid nanofluid over a rotating disk: an application in solar systems

Abstract

This current attempt explores the characteristics of variable viscosity and variable thermal conductivity of EMHD flow in which the shape factors like spherical versus laminar is considered for comparison purpose. Also, non-uniform heat source/sink and entropy generation are taken into count. We consider ethylene glycol of 50% and water of 50% mixture as base fluid. To convert the governing equations into ordinary differential equations (ODEs), self-similarity variables are used. The RK Fehlberg method has been used successfully to solve numerical sequential of ODEs. Active parameters such as magnetic field, electric field, Biot number, variable viscosity and variable thermal conductivity parameters are plotted on velocity profile, entropy, temperature and Bejan number. For the variable viscosity and thermal conductivity factors, the temperature rate increases. At the highest values of these parameters, the heat transmission rate is extremely high. This theoretical study is important for solar energy collectors, solar water heaters, solar energy conversion devices, solar PV (Photovoltaic) systems, solar thermal power fabrication, solar thermoelectric cells and radiators, among other things.