Passive flow control in microdevices using thermally responsive polymer solutions

TitlePassive flow control in microdevices using thermally responsive polymer solutions
Publication TypeJournal Article
Year of Publication2006
AuthorsStoeber, B., C. M. J. Hu, D. Liepmann, and S. J. Muller
JournalPhysics of Fluids
Volume18
Date PublishedMAY
ISSN1070-6631
Abstract

Thermally responsive polymer solutions have previously been used in microchannels with integrated heaters for active valving. Here we present a detailed study of the rheological behavior of these complex fluids, suggesting the broad range of conditions under which active valving could be used, along with an investigation of their use for passive microflow control in which viscous heating leads to channel blockage. We discuss the scaling of viscous heating in the channels under constant flow rate and constant pressure drop conditions. In the case of pressure-driven flow through a microchannel, we demonstrate that viscous heating can cause periodic gel formation leading to flow instabilities. Velocity fields above and below the gel temperature were mapped using digital particle image velocimetry; above the gel temperature, flow fluctuations may be caused by the competing mechanisms of thermothickening and shear-thinning. (C) 2006 American Institute of Physics.

URLhttp://dx.doi.org/10.1063/1.2204077%7D
DOI10.1063/1.2204077

a place of mind, The University of British Columbia

Electrical and Computer Engineering
2332 Main Mall
Vancouver, BC Canada V6T 1Z4
Tel +1.604.822.2872
Fax +1.604.822.5949
Email:

Emergency Procedures | Accessibility | Contact UBC | © Copyright 2021 The University of British Columbia