Comparative study on ethylene glycol based Ag-Al 2 O 3 and Al 2 O 3 nanofluids flow driven by electroosmotic and peristaltic pumping: a nano-coolant for radiators

Abstract

Abstract This paper aims to provide a comparative analysis of hybrid (Ag- Al 2 O 3) nanofluid and Al 2 O 3 mono nanofluid in a convective heat transfer process driven by electroosmotic and peristaltic pumping. Ethylene glycol (EG) due to its strong anti-freezing properties is taken as a base fluid. The features of mixed convection, magnetohydrodynamics, and Joule heating are also comprised in this study. The slip boundary conditions for axial velocity and temperature are employed at the walls of the microchannel in a porous environment and conditions of zero normal mass flux are imposed for the passive control of nanoparticles. This model is composed by using the Buongiorno flow model along with the modified Maxwell-Garnett model for thermal conductivity of hybrid nanofluids and Poisson-Boltzmann distribution for electric potential generated within the fluid medium. The problem is simplified under the approximations of lubrication theory and Debye–Hückel linearization and the numerical computations have been made through Maple 17 code. The graphical results of flow variables for various involved quantities are prepared and presented with a requisite interpretation. Moreover, contour graphs are also plotted for stream function in order to discuss the trapping phenomenon. The addition of a volume fraction of 9% of aluminum dioxide in ethylene glycol tends to raise the thermal conductivity of working fluid up to 28.97% however further addition of a small number of silver nanoparticles increases its thermal conductivity up to 53.57%. Due to this increment in thermal conductance, it is found that the efficiency of Ag- Al 2 O 3 nanofluid in the heat transfer mechanism is better than the Al 2 O 3 nanofluid. It is further reported that EG based hybrid nanofluid (Ag- Al 2 O 3) as nano-coolant is more applicable for radiators and other cooling systems as compared EG based (Al 2 O 3) nanofluid.