Mixed convection MHD boundary layer flow, heat, and mass transfer past an exponential stretching sheet in porous medium with temperature-dependent fluid properties

Abstract

The mixed convection MHD boundary layer flow, heat and mass transfer of a Newtonian fluid mixture across an exponentially stretched permeable sheet in porous medium with Soret and Dufour effects subject to temperature-dependent fluid properties have been investigated numerically. The distribution of temperature and concentration at the surface is supposed to grow exponentially. Temperature is considered to affect fluid viscosity and thermal conductivity. The guiding partial differential equations with appropriate boundary conditions are converted into coupled, nonlinear ordinary differential equations with variable coefficients via a similarity transformation. Matlab's built in solver bvp4c is used to find numerical solutions. Using a graphical approach, the effects of several emerging physical parameters on velocity, temperature and concentration distributions on a flow field of a chemically nonreacting fluid mixture are examined and discussed. Results are compared to earlier literature available and found to be in good agreement. Furthermore, this research demonstrates that flow, heat and mass transmission are greatly influenced by mixed convection parameters, magnetic field, Prandtl number, viscosity, conductivity, permeability, and Schmidt number. Skin friction grows for mixed convection parameter, magnetic, viscosity. Highest growths of wall temperature and wall concentration gradients are observed for Prandtl number and Schmidt number, respectively.

HIGHLIGHTS

• Heat and mass transfer rates increase with higher values of mixed convection parameters and Darcy parameter.

• To reduce heat transfer rate magnetic field may be used.

• Fluid with lower thermal conductivity and with higher Prandtl number may be employed to boost the cooling rate in conducting flows.

• Higher Schmidt enhances mass transfer rates.

• Suction stabilizes boundary layer growth.

• Soret effect can be used to separate light and medium molecular weight components from a fluid mixture and hence can be used for control of air pollution.

Keywords:

• Dufour
• mixed convection
• porous medium
• Soret
• suction
• variable thermal conductivity
• variable viscosity

Acknowledgments

The authors are extremely grateful to the authority of Kohima Science College, Jotsoma for providing financial support to carry out this work.