A numerical evaluation of flows through an SMX-Plus mixer

Abstract

A numerical investigation of the flow through an SMX+ mixer was undertaken in this study. Three elements were placed in series to assess various hydrodynamic parameters. Single-phase flows of different viscosities flowing at a hydraulic Reynolds number between 220 and 660 were considered to ensure turbulent conditions inside the mixer. The data was validated against pressure drop measurements collected under a wide range of hydrodynamic conditions. The results show that a three-dimensional velocity field dominate the flow within the mixer where the distribution of the strain rate and vorticity magnitudes undergo large fluctuations. The extensional efficiency was found to increase substantially in the first part of each mixer, indicating good dispersive behavior; however, its value decreased to values below 0.5 downstream of the last element. This was due to the presence of a significant rotational core as the fluid flowed farther from the last mixer. The core region of the flow spiraled on its axis as it moved downstream while the near-wall area whirled orthogonal to the flow direction. This also explained the persistence of a flatter velocity profile downstream of the mixing section. The energy dissipation rate and kinetic energy were also analyzed. © 2021 Institution of Chemical Engineers