Review of CFD modelling techniques for single‐phase and multiphase flow in static mixers

Static mixers enable compact and low‐energy intensification. However, predicting multiphase performance still requires computational fluid dynamics (CFD) coupled to population‐balance models. This review consolidates recent advances on turbulence closures, mesh/wall‐treatment practices, and CFD–population balance equation (PBE) couplings for Kenics, SMX/SMXL, LPD, HEV, and Q‐type geometries in liquid–liquid and gas–liquid flows. We compare Reynolds‐averaged Navier–Stokes (RANS) families (standard/re‐normalization group [RNG]/Realizable , SST) with LES/DES and outline accuracy–cost trade‐offs for pressure drop and the Sauter mean diameter . Sectional PBEs recover full drop size distributions, while quadrature method of moments (QMOM)/extended quadrature method of moments (EQMOM) capture and low‐order moments efficiently. We summarize guidance on targets, near‐wall modelling, and coupling strategies (one‐way/two‐way, Euler–Euler–PBE), and highlight common pitfalls in calibration/validation. Remaining gaps include scarce, high‐quality datasets with geometry‐resolved flow and mass‐transfer measurements, and limited cross‐regime benchmarks. We conclude with a practical checklist for selecting models and reporting practices to improve reproducibility and to support open, shareable datasets with varied interfacial properties.