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

Authors: Mete Avci, Orhan Aydin

Addresses: Department of Mechanical Engineering, Karadeniz Technical University, 61080 Trabzon, Turkey. ' Department of Mechanical Engineering, Karadeniz Technical University, 61080 Trabzon, Turkey

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.

Keywords: second law of thermodynamics; entropy generation; Bejan number; heat transfer; fluid flow; microscale geometries; MEMS; Knudsen number; Brinkman number; exergy; microtubes; microducts; parallel plates; viscous dissipation; velocity slip; temperature jump; irreversibilities; microfluidics.

DOI: 10.1504/IJEX.2007.013395

International Journal of Exergy, 2007 Vol.4 No.3, pp.286 - 301

Published online: 25 Apr 2007 *

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