Magnetohydrodynamics squeezing non-newtonian flows with and without nanofluid between two parallel plates in porous medium

Abstract

The wide applications of ultrahigh cooling devices in the current industries are necessary to improve the effectiveness of thermal devices. The development of an advanced heat transfer fluid known as nanofluid is very important to satisfy the high cooling rate standard. Conventional fluid such as water, ethylene glycol, or engine oil has limited heat transfer capability owing to the low thermal conductivity. Therefore, the dispersion of metallic nanoparticles in the fluid is implemented to boost the thermal conductivity of the conventional fluid. The utilization of nanofluid in cooling devices has shown good results in energy saving and emission reduction. Furthermore, the flow of non-Newtonian fluid, especially Casson and Jeffrey fluid, has been acknowledged due to its flow behaviour depending on the shear stress applied. The fluid acts as a solid if the applied stress exerted is lower than yield stress, whereas the fluid begins to flow if the applied stress exerted is more than yield stress. Motivated by the significant features of non-Newtonian fluid and nanofluid, the aim of this study is to investigate the unsteady magnetohydrodynamic flow of Casson and Jeffrey fluids with and without nanoparticles embedded in a porous medium with slip boundary condition. The motion of fluid flow is generated by squeezing between two parallel plates with external stress. The effects of viscous dissipation and chemical reaction on fluid flow are also investigated. The nonlinear governing equations are transformed into ordinary differential equations using a similarity transformation and solved numerically via Keller-box method. The numerical and graphical results are obtained through MATLAB software. Meanwhile, the present results are validated by comparing them with the published results. Hence, a good agreement is obtained. The graphical results of velocity, temperature, and concentration profiles are analysed with various physical parameters. The results show that the increment of the fluid velocity and the wall shear stress in Casson and Jeffrey fluids with and without nanoparticles is caused by squeezing of plates. Meanwhile, the velocity, temperature, and concentration profiles decrease with the presence of magnetic field and also Casson and Jeffrey fluid parameters. It is discovered that the rate of heat transfer and temperature profile increase with the impacts of viscous dissipation and thermophoresis. In nanofluid, the rate of mass transfer decelerates for increasing Brownian motion, while it elevates when chemical reaction and thermophoresis increase.