Computation of entropy generation in dissipative transient natural convective viscoelastic flow

Kumar, M; Reddy, GJ; Kiran, GR; Aslam, MAM; Beg, OA

Abstract

Entropy generation is an important aspect of modern thermal polymer processing optimization. Many polymers exhibit strongly non-Newtonian effects and dissipation effects in thermal processing. Motivated by these aspects in this article a numerical analysis of the entropy generation with viscous dissipation effect in an unsteady flow of viscoelastic fluid from a vertical cylinder is presented. The Reiner-Rivlin physical model of grade two (second grade fluid) is employed which can envisage normal stress variations in polymeric flow-fields. Viscosity variation is included. The obtained governing equations are resolved using implicit finite difference method of Crank-Nicolson type with well imposed initial and boundary conditions. Key control parameters are the second-grade viscoelastic fluid parameter (β), viscosity variation parameter (γ) and viscous dissipation parameter (ε). Also, group parameter (BrΩ-1), Grashof number (Gr) and Prandtl number (Pr) are examined. Numerical solutions are presented for steady-state flow variables, temperature, time histories of friction, wall heat transfer rate, entropy and Bejan curves for distinct values of control parameters. The results specify that entropy generation decreases with augmenting values of β, γ and Gr. The converse trend is noticed with increasing Pr and BrΩ-1. Furthermore, the computations reveal that entropy and Bejan lines only occur close to the hot cylinder wall.

Citation

Kumar, M., Reddy, G., Kiran, G., Aslam, M., & Beg, O. (2019). Computation of entropy generation in dissipative transient natural convective viscoelastic flow. Heat Transfer - Asian Research, 48(3), 1067-1092. https://doi.org/10.1002/htj.21421

• Journal Article Type: Article
• Acceptance Date: Dec 21, 2018
• Online Publication Date: Jan 16, 2019
• Publication Date: Jan 16, 2019
• Deposit Date: Jan 7, 2019
• Publicly Available Date: Jan 16, 2020
• Journal: Heat Transfer- Asian Research
• Print ISSN: 1099-2871
• Electronic ISSN: 1523-1496
• Publisher: Wiley
• Volume: 48
• Issue: 3
• Pages: 1067-1092
• DOI: https://doi.org/10.1002/htj.21421
• Publisher URL: https://doi.org/10.1002/htj.21421
• Related Public URLs: https://onlinelibrary.wiley.com/journal/15231496
• Additional Information: Projects : Entropy generation optimization in thermo-rheological coating dynamics