Unsteady MHD Flow of Nanofluid with Variable Properties over a Stretching Sheet in the Presence of Thermal Radiation and Chemical Reaction

Musa Antidius Mjankwi,Eunice W Mureithi,Verdiana Grace Masanja,Makungu Ng’Oga James

doi:10.1155/2019/7392459

Abstract

The unsteady magnetohydrodynamics (MHD) flow of nanofluid with variable fluid properties over an inclined stretching sheet in the presence of thermal radiation and chemical reaction is studied taking into account the effect of variable fluid properties in thermal conductivity and diffusion coefficient. The governing partial differential equations are transformed into ordinary differential equations by using similarity transformation. The numerical solutions of the problem are obtained by using the fourth order Runge-Kutta method in line with the shooting technique. It is found that the increase in both thermal conductivity and radiative heat flux decreases the heat transfer rate but increases the skin friction and mass transfer rates. It is further observed that the increase in porosity parameter and magnetic field reduces the skin friction, heat, and mass transfer rates.

Highlights

The study concerned with the fluid flow over a stretching sheet has created many applications in industries among which are polymer industries, aerodynamic extrusion of plastic sheets, glass-fiber production, condensation process of a metallic plate in a cooling bath, and glass
Erickson et al [4] extended the Sakiadis [1] study by introducing the effects of momentum, heat transfer, and mass transfer on the surface that is moving at constant speed
This study was further extended by Gupta [5] who added new parameters of suction, injection and considered the sheet to be stretched with a linear speed

Summary

Introduction

The study concerned with the fluid flow over a stretching sheet has created many applications in industries among which are polymer industries, aerodynamic extrusion of plastic sheets, glass-fiber production, condensation process of a metallic plate in a cooling bath, and glass. Experimental studies have established that the physical properties of magnetic nanofluids change with varying average particles size, changing in nanoparticle shape and the nature of base fluid used as presented by Rao and Ranganayakulu [25] These findings influenced researchers like Mutuku [26] who proposed the modifications of some cooling systems (e.g., car radiators) or cooled materials (e.g., stretched sheet) by including the effect of external magnetic field against nanofluid (coolant fluids) so as to control the fluid flow for effective cooling. The effects of nondimensional governing parameters such as variable thermal conductivity, variable diffusion coefficient, radiative heat flux, chemical reaction, porous medium, unsteadiness parameter, magnetic parameter, Prandtl number, Eckert number, Schmidt number, concentration Grashof number, thermal Grashof number, inclination angle and suction velocity parameter on dimensionless velocity, temperature, concentration profiles as well as skin friction, and Nusselt and Sherwood numbers will be discussed when magnetic nanofluids are applied as coolant fluid under the effects of external magnetic fields

Formulation of the Problem

Numerical Solution of the Problem

Results and Discussion

Conclusion

A: Unsteadiness parameter