Second Law Analysis for Variable Viscosity Hydromagnetic Boundary Layer Flow with Thermal Radiation and Newtonian Heating

Oluwole Daniel Makinde

doi:10.3390/e13081446

Abstract

The present paper is concerned with the analysis of inherent irreversibility in hydromagnetic boundary layer flow of variable viscosity fluid over a semi-infinite flat plate under the influence of thermal radiation and Newtonian heating. Using local similarity solution technique and shooting quadrature, the velocity and temperature profiles are obtained numerically and utilized to compute the entropy generation number. The effects of magnetic field parameter, Brinkmann number, the Prandtl number, variable viscosity parameter, radiation parameter and local Biot number on the fluid velocity profiles, temperature profiles, local skin friction and local Nusselt number are presented. The influences of the same parameters and the dimensionless group parameter on the entropy generation rate in the flow regime and Bejan number are calculated, depicted graphically and discussed quantitatively. It is observed that the peak of entropy generation rate is attained within the boundary layer region and plate surface act as a strong source of entropy generation and heat transfer irreversibility.

Highlights

Theoretical study of thermodynamic irreversibility in hydromagnetic boundary layer flow in the presence of thermal radiation appears to be increasingly important due to its various applications in engineering and industries [1,2] such as in the design of cooling systems for electronic devices, in the field of solar energy collection, geothermal reservoirs, heat exchangers, thermal insulation, enhanced oil recovery, packed-bed catalytic reactors, cooling of nuclear reactors, etc
This study extends the work of Aziz [25] to include the combined effects of magnetic field, viscous dissipation, radiative heat transfer and entropy generation analysis
The results have been compared with the one reported by Aziz [18] as shown in Table 1 for constant viscosity fluid without the magnetic field, thermal radiation and viscous dissipation effects and it is found that they are in good agreement

Summary

Introduction

Theoretical study of thermodynamic irreversibility in hydromagnetic boundary layer flow in the presence of thermal radiation appears to be increasingly important due to its various applications in engineering and industries [1,2] such as in the design of cooling systems for electronic devices, in the field of solar energy collection, geothermal reservoirs, heat exchangers, thermal insulation, enhanced oil recovery, packed-bed catalytic reactors, cooling of nuclear reactors, etc. Several excellent studies on hydromagnetic boundary layer flows with thermal radiation have been communicated [6,7,8] These forgoing research works have covered a wide range of problems involving the hydromagnetic boundary layer flow and heat transfer phenomenon; they have been restricted, from thermodynamic point of view, to only the first law analysis. Entropy generation is closely associated with thermodynamic irreversibility, which is encountered in all heat transfer processes [10]

Methods

Results

Conclusion