Second-law analysis of heat and fluid flow in microscale geometries

Avci M., Aydin O.

INTERNATIONAL JOURNAL OF EXERGY, vol.4, no.3, pp.286-301, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 4 Issue: 3
  • Publication Date: 2007
  • Doi Number: 10.1504/ijex.2007.013395
  • Journal Name: INTERNATIONAL JOURNAL OF EXERGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.286-301
  • Keywords: second-law of thermodynamics, entropy generation, Bejan number, microscale, MEMS, Knudsen number, Brinkman number, LAMINAR FORCED-CONVECTION, ENTROPY GENERATION, MICROCHANNELS, DUCT, CHANNEL
  • Karadeniz Technical University Affiliated: Yes

Abstract

In this study, the second law analysis of thermodynamics is applied to two different microgeometries: microtube and microduct, between two parallel plates. Hydrodynamically and thermally fully developed flow with constant properties is examined. Microscale effects are included in the analysis in terms of the viscous dissipation, the velocity slip and temperature jump. Using the previously obtained velocity and temperature profiles, a parametric study is carried out to determine the combined effects of the Brinkman number, Br, and the Knudsen number, Kn, on the entropy generation. Entropy generation is shown to decrease with an increase in Kn while increasing Br results in increasing entropy generation.