Investigation of comparative entropy in different nanofluids inspired by solar radiations and unsteady effects: Model analysis for permeable channel

Entropy analysis in nano as well as conventional fluids is of paramount interest and highly affected by the active physical quantities. The research provides comprehensive comparative entropy performance of multiple nanofluids in the view of model quantities. The physical model considered in the presence of solar radiations, dissipation energy and magnetic field. The multiple fluids squeezed in a channel formed by two horizontal sheets with upper non-stationary surface. The entropy modeling performed using similarity variables for transient flow and governing laws. The numerical approach (RK method coupled with shooting scheme) is used for entropy results which obtained for ternary, hybrid, nano and base fluids. It is found that entropy optimized in ternary nanofluid while hybrid, nano and common fluids caused reduction in it. Dissipation effects ($Ec=0.1,0.3,0.5,0.7$) increases the entropy while significant reduction is observed for ${\Omega }_1=0.1,0.2,0.3,0.4$. The solar radiations in the range of $Rd=1.0$ to $Rd=7.0$ contributes effectively to improve entropy phenomena in both inward and outward plate movement. Thus, the system can be maintained at low entropy by strengthening the effects of ${\Omega }_1$ and optimum entropy is subject to Eckert number, $\alpha =0.1,0.2,0.3,0.4$, radiations ($Rd=1.0,3.0,5.0,7.0$) for $S>0.0$ and $S<0.0$, respectively.