Entropy analysis of hybrid nanofluid flow in a porous medium with variable permeability considering isothermal/isoflux conditions

Abstract

The presented article deals with the mixed convection flow of a hybrid nanofluid comprising of copper and silver nanoparticles flowing in a porous medium having variable permeability. The porous medium is embedded in a parallel plate inclined channel where the plates are subjected to isothermal–isoflux conditions. Two cases are considered where the isothermal–isoflux conditions are interchanged: isothermal–isoflux and isoflux–isothermal conditions. Moreover, variation in permeability of the porous medium is taken for two cases where the permeability increases along the width of the channel for one case and the permeability decreases along the width of the channel for the other case. The homotopy analysis method is utilised to solve the nonlinear differential equation governing the flow of the nanofluid. To verify the solution, a reduced form of the governing equation is solved analytically and the answers were compared. Entropy generation analysis is then conducted in a manner that the flow parameters are varied individually. An interesting observation is that the isothermal–isoflux condition is more sensitive towards the variation in the parameter values. Another noteworthy observation is that the case of decreasing the permeability parameter of the porous medium leads to a higher entropy generation for all parameter values presented in the study. • Hybrid nanofluid flowing in a porous medium having non – uniform permeability is investigated using entropy generation analysis. • Two thermal boundary conditions are considered: isothermal – isoflux and isoflux – isothermal conditions. • Entropy generated in the flow was found to be maximum near the upper part of the wall. • Isoflux – isothermal boundary condition was found to generate more entropy for all cases of the investigation.