Chaos and mixing in NETmix

Abstract

NETmix is a network of mixing chambers interconnected by channels, in which the most efficient mixing occurs under chaotic flow regimes. Chaos is highly influenced by the topology, particularly by the ratio chamber diameter/channel width, D/d. In this work, micromixing in NETmix is characterized through Lagrangian Mixing Simulation (LMS), which enables to establish the relation between the degree of mixing and the topology, D/d. The degree of mixing is then related with the Eulerian chaoticity from hydrodynamics and spectral analysis. The best mixing is obtained at D/d = 6.65 and is associated to a thin 8 shaped strange attractor. The spectral analysis shows a principal oscillation frequency at St = 0.13. Since the quasi-periodic regime is alternated with chaotic behavior, NETmix has an intermittent bifurcation. For the NETmix system, orderly flows in the quasi-periodic regime have higher mixing intensity than less orderly flows in the weak or strong chaotic regimes.