Eur. Phys. J. Plus (2017) 132: 404
https://doi.org/10.1140/epjp/i2017-11704-5

Regular Article

Entropy generation in hydromagnetic boundary flow under the effects of frictional and Joule heating: Exact solutions

¹ Department of Mathematics, COMSATS Institute of Information Technology, Park Road, Chak Shahzad, Islamabad, Pakistan
² Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, 81310, Johor, Malaysia

^* e-mail: sharidan@utm.my

Received: 29 May 2017
Accepted: 14 August 2017
Published online: 29 September 2017

Abstract

The objective of the present article is to discuss the effects of viscous dissipation and Joule heating on entropy generation in a hydromagnetic boundary layer flow. Governing equations are reduced to self-similar equations via suitable similarity transformations. The expressions for the volumetric entropy generation rate and the Bejan number are also obtained using similarity transformations. The exact solution of the transformed energy equation is computed using the Laplace transform treatment. The obtained exact solutions are utilized to calculate the entropy generation number and the Bejan number. The impacts of Prandtl number, viscous dissipation parameter (Eckert number), magnetic parameter, mass suction and temperature difference parameter on entropy generation and Bejan number are discussed graphically. The increasing value of the temperature difference parameter reduces the entropy generation. The entropy generation increases with the increasing values of the magnetic parameter, the Eckert number, the mass suction parameter and the Prandtl number.