Abstract: To analyze the internal information in microreactors, numerical simulations of the micromixing process in a T-type round tube, a T-type square tube, and a square Y-type microreactors were carried out using computational fluid dynamics (CFD) methods. The results simulated by Laminar-Finite-Rate model were consistent with the experimental data reported in the literature, which demonstrated the accuracy and reliability of the chosen CFD model. The flow field, velocity distribution, distributions of H⁺ and I₂, and the distribution of the segregation index X_S of each microreactor in the Villermaux-Dushman reaction system were analyzed, which provided a reference for the evaluation of the micromixing efficiency in microreactors. The results showed that the flow of fluids in all three microreactors was laminar, and H⁺ was quickly and completely consumed in the T-type round tube microreactor, whereas it was always present in the T-type square tube and Y-type square tube microreactors. The segregation index X_S was small in all three microreactors, which showed excellent micromixing efficiency.

Key words: computational fluid dynamics, microreactor, Villermaux-Dushman reaction, micromixing efficiency, segregation index