title: Dispersion in cylindrical channels on the laminar flow at low Fourier numbers.
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.
authors.affiliation: 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.
authors.forename: Witold
authors.initials: W
authors.lastname: Kucza
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Cracow, Poland.
authors.forename: Juliusz
authors.initials: J
authors.lastname: Dąbrowa
authors.affiliation: AGH University of Science and Technology, Faculty of Materials Science and Ceramics, Al. Mickiewicza 30, 30-059 Cracow, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Nawara
keywords: Diffusion coefficient; Flow injection system; Impedance measurements; Numerical modeling; Optimization