Mixing Surface Tracking Method: A Lagrangian Fluid Tracking-Based Approach for CFD Micromixing Characterization and Its Application in T-Shaped Microreactors

The mixing surface tracking (MS-T) method, a reaction-free approach based on Lagrangian trajectories of fluid elements in CFD simulation, was developed to characterize micromixing under steady-state turbulent flow in T-shaped microreactors. By defining mixing surfaces (MSs) as assemblies of fluid elements of equal mixing time, the evolution of MSs─which visually represented both fluid motion and concentration changes in the mixing process─was quantified using mixing intensity (IM). The micromixing time (tm) was defined as the mixing time required for IM to reach 0.95. The tm values obtained by the MS-T method showed good agreement with those derived from a conventional I–/IO3– reaction system (Villermaux/Dushman method) combined with the incorporation model, confirming the reliability of the MS-T method on micromixing evaluation.