Dispersion in cylindrical channels on the laminar flow at low Fourier numbers

Witold Kucza; Juliusz Dąbrowa; Katarzyna Nawara

doi:10.1016/j.aca.2015.04.049

Dispersion in cylindrical channels on the laminar flow at low Fourier numbers

Anal Chim Acta. 2015 Jun 30:881:90-7. doi: 10.1016/j.aca.2015.04.049. Epub 2015 Apr 27.

Authors

Witold Kucza¹, Juliusz Dąbrowa², Katarzyna Nawara²

Affiliations

¹ AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Cracow, Poland. Electronic address: witek@agh.edu.pl.
² AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Cracow, Poland.

PMID: 26041524
DOI: 10.1016/j.aca.2015.04.049

Abstract

A numerical solution of the uniform dispersion model in cylindrical channels at low Fourier numbers is presented. The presented setup allowed to eliminate experimental non-idealities interfering the laminar flow. Double-humped responses measured in a flow injection system with impedance detection agreed with those predicted by theory. Simulated concentration profiles as well as flow injection analysis (FIA) responses show the predictive and descriptive power of the numerical approach. A strong dependence of peak shapes on Fourier numbers, at its low values, makes the approach suitable for determination of diffusion coefficients. In the work, the uniform dispersion model coupled with the Levenberg-Marquardt method of optimization allowed to determine the salt diffusion coefficient for KCl, NaCl, KMnO4 and CuSO4 in water. The determined values (1.83, 1.53, 1.57 and 0.90)×10(-9)m(2)s(-1), respectively, agree well with the literature data.

Keywords: Diffusion coefficient; Flow injection system; Impedance measurements; Numerical modeling; Optimization.