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N. Poumaëre, B. Pier and F. Raynal
Laboratoire de mécanique des fluides et d'acoustique, École centrale de Lyon – CNRS – Université Claude-Bernard Lyon 1 – INSA, 36 avenue Guy-de-Collongue, 69134 Écully cedex, France
Physical Review E 106, 015107 (13 pages) (2023)
We investigate the distributions of residence time for in-line chaotic mixers; in particular, we consider the Kenics, the F-mixer, and the multilevel laminating mixer and also a synthetic model that mimics their behavior and allows exact mathematical calculations. We show that whatever the number of elements of mixer involved, the distribution possesses a $t^{-3}$ tail, so that its shape is always far from Gaussian. This $t^{-3}$ tail also invalidates the use of second-order moment and variance. As a measure for the width of the distribution, we consider the mean absolute deviation and show that, unlike the standard deviation, it converges in the limit of large sample size. Finally, we analyze the performances of the different in-line mixers from the residence-time point of view when varying the number of elements and the shape of the cross section.
hal-03727867
2022b_poumaere_pre.pdf