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Effect of hydrodynamic heterogeneity on micromixing intensification in a Taylor–Couette flow (TC) reactor with variable configurations of inner cylinder has been investigated by adoption of a parallel competing iodide‐iodate reaction system. Two types of inner cylinder, circular inner cylinder and lobed inner cylinder (CTC and LTC), were used to generate hydrodynamic heterogeneity, focusing on the effects of the Reynolds number, the acid concentration, and the feeding time on the micromixing performance. Segregation index (Xs) was employed to evaluate the micromixing efficiency. It is revealed that Xs decreases with the increase of Reynolds number and feeding time but increases with the increase of acid concentration for both the CTC and LTC. However, the LTC does present a better micromixing performance at various operating conditions than that of the CTC as affirmed by both the experimental and computational fluid dynamics simulation results. [ABSTRACT FROM AUTHOR]

• A multiphase CFD model coupling the cavitation model and chemical reactions is developed for the first time. • Influences of acoustic cavitation on "local" micro-mixing process in the CIJR are investigated. • An increase in the power of ultrasound can improve the micro-mixing efficiency. • Ultrasound has larger effects on the meso-mixing process than micro-mixing process at the tip of transducer head. • Meso-mixing process controls the overall process with or without applying ultrasound. Studies on the influences of ultrasound-induced cavitation on the micro-mixing process in a confined impinging jet reactor (CIJR) are still lacking. In the present study, experimental and numerical approaches are employed to investigate the effects of ultrasound intensification on the mixing processes in a CIJR. The numerical results are experimentally validated. The model is also coupled with chemical reactions for the first time. It is found that local eddies generated by the collapse of acoustic microbubbles and "turbulence"-like acoustic streaming can significantly reduce the micro-mixing time. In all cases, the micro-mixing efficiency is found to increase with an increase in the power of ultrasound. A reduction of 15–24% in micro-mixing time can be achieved at the inlet velocity of 0.2m/s when the power of ultrasound increases from 122.5W to 175W. It is also found that the effect of ultrasound intensification on the meso-mixing process is larger than that on the micro-mixing process in the vicinity of transducer head. The ratio of micro-mixing time to meso-mixing time in the case of P ultra =175W can be 88% larger than that in the case of P ultra =0W in the front of the transducer head at Re in =5000. [Display omitted] [ABSTRACT FROM AUTHOR]