Effect of Magnetic Field on Entropy Generation Due to Laminar Forced Convection Past a Horizontal Flat Plate

Mohammed Q Al-Odat,Moh'D A Al-Nimr,Renhe A Damseh

doi:10.3390/e6030293

Abstract

Magnetic field effect on local entropy generation due to steady two-dimensional laminar forced convection flow past a horizontal plate was numerically investigated. This study was focused on the entropy generation characteristics and its dependency on various dimensionless parameters. The effect of various dimensionless parameters, such as Hartmann number (Ha), Eckert number (Ec), Prandtl number (Pr), Joule heating parameter (R) and the free stream temperature parameter (θ∞) on the entropy generation characteristics is analyzed. The dimensionless governing equations in Cartesian coordinate were solved by an implicit finite difference technique. The solutions were carried out for Ha2=0.5-3, Ec=0.01-0.05, Pr=1-5 and θ∞=1.1-2.5. It was found that, the entropy generation increased with increasing Ha, Ec and R. While, increasing the free stream temperature parameter, and Prandtl number tend to decrease the local entropy generation.

Highlights

The optimal design of thermal systems can be achieved by minimizing entropy generation in the systems
This study indicated that entropy generation is increased as the Reynolds number and the buoyancy parameter increased
This is because the presence of the transverse magnetic field creates a resistive force similar to the drag force that acts in the opposite direction of the fluid motion, causing the velocity of the fluid to decrease

Summary

Introduction

The optimal design of thermal systems can be achieved by minimizing entropy generation in the systems. Tasnim et al [4] presented an analytical work to study the first and second laws (of thermodynamics) characteristics of flow and heat transfer inside a vertical channel made of two parallel plates embedded in a porous medium and under the action of transverse magnetic field. They demonstrated that the group parameter have a significant effect on entropy generation such that the higher values of group parameters cause higher entropy generation. The common outcome of references [12,13,14,15] is that the presence of magnetic field tends to slowdown the fluid motion and increases the fluid temperature

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Conclusion