Role of minimization entropy generation and heat transfer on the nanofluid peristaltic flow via Reiner-Philippoff model

Abstract

The primary objective of this study is to explore the effects of minimizing entropy generation in the context of peristaltic flow within an asymmetric tapered channel, using Buongiorno’s nanofluid model to account for pseudoplastic and dilatant behaviors of the nanofluid. To accurately represent the non-Newtonian characteristics of the fluid, we employ the Reiner-Philippoff (RPh) fluid model, known for its intricate nature among non-Newtonian models. In the RPh model, the relationship between shear stress and velocity gradient is nonlinear, and it also accounts for the implicit coupling between stress and deformation rate, presenting a formidable challenge. Our investigation incorporates the effects of thermophoresis motion, the viscosity parameter of the RPh fluid, and Brownian motion into the governing equations. We simplify these equations under the assumptions of low Reynolds numbers and long wavelengths. Subsequently, we numerically solve the resulting nonlinear equations. We thoroughly discuss the significant impact of RPh nanofluid parameters on entropy generation and the Bejan number by presenting graphical representations. Notably, we observe that the fluid transitions from a dilatant behavior to Newtonian behavior and from Newtonian behavior to pseudoplastic behavior as we vary the RPh fluid parameter. Furthermore, we briefly address the influence of thermophoretic diffusion, the Brinkman number, the RPh fluid parameter, Prandtl number, and Brownian motion parameters on entropy production and the Bejan number. It is experimented that the entropy generation is less for dilatants fluid and higher for pseudoplastic fluids. We can also notice that the entropy generation significantly increases by Brinkman number Br for both types of fluid. We also provide a mathematical and graphical examination of the effects of all these significant parameters.