Prediction of the reaction yield in a X-micromixer given the mixing degree and the kinetic constant

Understanding flow regimes and mixing in microreactors is crucial for achieving high reaction yields. This study combines simulations and experiments in an X-microreactor up to Reynolds number (Re) 600. For Re > 375, an unsteady periodic regime is observed with a collapsing central vortical structure and symmetric vorticity shedding. Counterrotating vortices form, merge, and recreate the central vortex. Despite increased mixing in this regime, reaction yield remains similar due to reduced reactant residence time. A model predicting reaction yield based on mixing degree and nominal kinetic constant is developed, successfully encompassing all flow regimes and Damk\"ohler numbers (0.1 Da 10³).