Investigation into Droplet Size Distribution and Turbulent Mixing Enhancement Performance in a Lightnin Static Mixer

The CFD–PBM coupled model was utilized to investigate the liquid–liquid turbulent mixing and enhancement performance in a Lightnin static mixer (LSM). The droplet size distribution (DSD), Sauter mean diameter (d32), and mixing index of the LSM were studied. The effects of the length–diameter ratio (l/D0), gap-diameter ratio (G/D0), and arrangement were analyzed. The correlation among d32/D0, the Fanning friction factor (f), and the Weber number was established. The d32 and Poiseuille number calculated from simulation were in good agreement with experiments, and the d32 decreased by 93.52%. Meanwhile, the analysis of turbulent higher-order moments of DSD showed that the DSD in the L–R LSM with l/D0 = 1 was narrower than that in other static mixers. Gray relational analysis revealed that the addition of gaps in the LSM can improve distribution mixing performance with a lower pressure drop. The L–R LSM with l/D0 = 1 and G/D0 = 1 is recommended based on the enhancement factor and gray analysis.