Irreversibility Analysis of Variable Thermal Conductivity MHD Radiative Flow in a Porous Channel With Different Nanoparticles

The entropy generation on radiative heat transfer performance in the flow of variable thermal conductivity, optically thin viscous water-based nanofluid with an external magnetic field through a porous parallel channel is investigated in the present work. Three types of nanoparticles, Cu, TiO2, and Al2O3, are used to observe their performance. The fluid temperature in the channel varies due to the asymmetric heating of the walls as well as viscous dissipation. Our approach uses the power series from the governing nonlinear differential equations for small values of the thermal conductivity variation parameter which are then analyzed by various generalizations of the Hermite- Pade approximation method. The influences of the pertinent governing flow parameters on velocity, temperature, thermal conductivity criticality conditions, and entropy generation are discussed extensively, both numerically and graphically. A stability analysis has been performed for the local rate of heat transfer, which signifies that the lower solution branch is stable and physically acceptable whereas the upper solution branch is unstable. It is interesting to note that the entropy generation of the system increases at the two porous plates as well as that the fluid friction irreversibility is dominant there.