Abstract

Micromixing was experimentally studied by the iodide–iodate technique in a free impinging-jets microreactor (FIJMR) with differentiated sampling and in a laboratory reactor with a magnetic stirrer. In the latter case, the quality of micromixing was extremely low (segregation index X_s = 0.52 ± 0.03). Micromixing was studied at different jet diameters (d_j = 0.55, 1.0, and 2.0 mm), distances from the nozzle exit to the collision point (L = 5, 20, and 40 mm), and liquid flow rates. The jet diameter and the distance from the nozzle exit to the collision point have a significant effect on the quality of micromixing. At relatively low Weber numbers (We < 2000) and at L/d_j ≈ 73, the so-called “varicose” instability of jets appears, as a result of which the jets break up into drops before the moment of collision. At We > 2000, the jet stabilizes due to an increase in the kinetic energy. At We = 6000, X_s for L = 40 mm becomes the same as for L = 5 mm. For aqueous solutions, the optimum diameter is 1 mm as it provides relatively high performance with a high quality of micromixing, while the dispersion of droplets and filaments to the periphery is minimum (or absent).