Entropy generation in electroosmotically aided peristaltic pumping of MoS ₂ Rabinowitsch nanofluid

Abstract

The main emphasis of this article is to compare the heat transfer performance of two different nanofluids i.e. carboxy-methyl-cellulose (CMC) + water-based molybdenum dioxide (MoS ₂) nanofluid and kerosene oil-based molybdenum dioxide nanofluid during the fluid flow through a symmetric microchannel which is pumped by the mechanism of peristalsis and electroosmosis. The energy dissipated by Joule heating and viscous dissipation is also taken into account. An analysis of volumetric entropy generation is also conducted. Rabinowitsch fluid model is employed to characterize the shear-thinning behavior of CMC + water solution and Newtonian fluid properties of kerosene oil. The mathematical model for the problem is formulated by the Navier–Stokes, energy equation, and Buongiorno fluid model in combination with the Corcione model for thermal conductivity and viscosity of the nanofluid. Further, the Poisson–Boltzmann equation is utilized to compute the potential generated across the electric double layer. The homotopy perturbation technique is employed to compute the approximate solutions for temperature and nanoparticle volume fraction and exact solutions are obtained for velocity and the stream function. Salient features of the fluid flow are illustrated with the aid of graphical results. Contour plots for stream function are prepared for flow visualization. A comparison of heat transfer performance and entropy generation between both working fluids is presented. It is observed that aqueous solution modified by CMC and nanoparticles possess a higher heat transfer tendency and less entropy is generated in this case when compared with other nanofluid i.e. MoS ₂/kerosene oil nanofluid under the same physical conditions. It is further noted that fluid flow can be controlled by the strength of the applied electric field. Upon increasing electroosmotic parameters, there is a very minute rise in volumetric entropy generation in the case of MoS ₂/CMC + water nanofluid. However, there is a substantial rise in entropy generation for MoS ₂/kerosene oil nanofluid.