Depletion of cross‐stream diffusion in the presence of viscoelasticity. Issue 12 (3rd August 2015)

• Record Type: Journal Article
• Authors: Sadeghi, Arman
• Is Part Of: AIChE journal. Volume 61:Issue 12(2015:Dec.)
• Page Start: 4533
• Page End: 4541
• Publication Date: 2015-08-03
• Subjects: electroosmotic flow -- T‐sensor -- viscoelastic fluids -- cross‐stream diffusion; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; 660.28
• DOI: 10.1002/aic.14955
• Languages: English
• ISSNs: 0001-1541

Abstract

Abstract : An effort to analyze the viscoelasticity effects on transverse transport of neutral solutes between two miscible streams in an electrokinetic T‐sensor is presented. The analysis is based on an approximate analytical solution for the depthwise averaged concentration, assuming a channel of large width to depth ratio for which a one‐dimensional profile is sufficient for describing the velocity field. We show that the solution derived is surprisingly accurate even for very small channel aspect ratios and the maximum error reduces to only about 1% when the aspect ratio is 5. The developed model reveals that the mixing length for a viscoelastic fluid may be by far larger than that for a Newtonian fluid. Moreover, the Taylor dispersion coefficient for electroosmotic flow of viscoelastic fluids, which its determination is a main part of the analysis, is found to be an increasing function of both the elasticity level and the EDL thickness. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4533–4541, 2015