MHD Pulsating flow and entropy analysis of micropolar nanofluid in a vertical channel with thermal radiation

Abstract

In this paper, we explore the pulsating flow magneto-hydrodynamic (MHD) unsteady flow of a micropolar nanofluid in a vertical channel by applying Buongiorno’s nanofluid model with entropy analysis. The effects of Brownian motion, thermophoresis, and Joule heating (Ohmic heating) are taken into account. The considered model is important in the study of biological fluid modeling, polymer engineering, sediments in rivers, and nano-drug delivery. A perturbation approach is used to convert the partial differential equations (PDEs) into ordinary differential equations (ODEs), and are subsequently solved by adopting the shooting technique with the help of the Runge-Kutta fourth-order method. The flow variables like velocity, microrotation, temperature and nanoparticle concentration are graphically depicted and discussed in detail for different values of physical parameters.

Nowadays, the scientific research of nanofluids is a highly recommended area in various domains such as mechanical systems, transformer cooling in vehicles, applications in biomedical, coolant systems, and so on. Nanofluids are a comparatively current category of heat transfer have fascinated much observation of researchers from previous generations around the globe. The section of nanofluids was first established by Choi [1]. To characterize a fluid including solid nanoparticles with a size typically of (1-100 nm) suspended in a fluid. Buongiorno [2] initialized the impacts of Brownian motion and thermophoresis diffusion are a major fact for the improvement of heat and mass transfer. Kumar et al. [3] examined the hydromagnetic pulsative flow of Casson nanofluid in a channel by using the Buongiorno model. The non-Newtonian fluid is observed as blood and it is classified as the micropolar fluid. The concept of the micropolar fluid model was primarily pioneered by Eringen in (1966) [4] and later extended into a thermo-micropolar fluid to explicate the properties of polymeric fluids, liquid crystals, colloidal suspensions, animal and human blood. In such fluid is characterized by microstructures, rigid and arbitrarily focused particles on microrotation of fluid components. Eringen [5,6] formulated a much complex structure for simulating effective micro-rheological properties and areas of applications in various industrial and engineering fields like chemical engineering, synovial fluid, biofluids, semi-circular canal fluids, gastric liquids, and slurry technologies.