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Advances in Mechanical Engineering
Volume 2013 (2013), Article ID 950681, 7 pages
http://dx.doi.org/10.1155/2013/950681
Research Article

Effective Resistance of Gas Flow in Microchannels

Department of Engineering Mechanics and CNMM, Tsinghua University, Beijing 100084, China

Received 6 December 2012; Accepted 4 February 2013

Academic Editor: Tomoaki Kunugi

Copyright © 2013 Xiao-Dong Shan and Moran Wang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The resistance of gas flow in microchannels is higher because of the relatively more importance of interfacial effects at microscale. We studied the effective resistance of gas from the wall interactions, the ends effect, and the rarefication effect quantitatively using the three-dimensional (3D) direct simulation Monte Carlo (DSMC) method. The effective resistance is enhanced by the wall interactions, increasing exponentially as the concerned walls distance decreases. For short microchannels, the ends effects from both inlet and outlet also raise the effective resistance of gas flow in microchannels following a reciprocal exponential relationship with the aspect ratio of length to height. The gas rarefication strengthens the effective resistance enhancement by either the wall interaction effects or the ends effects. This work turns a complicated micromechanical problem into simple available formulae for designs and optimization of microengineering.