Abstract Summary (Max 250 words)
This work focuses on a novel method that provides a unique solution to the closure problem occurring in reactive turbulent flows. So far, closure models have been developed for both single and competitive reactions, such as competitive–parallel and competitive–consecutive schemes; however, more complex systems have not yet been properly analyzed. In particular, this work focuses on the diazo-coupling test reaction, which is one of the most commonly recommended chemical probe approaches for investigating micromixing. The closure is based on an assumed mixture fraction function for a non-reactive scalar, accurately describing mixing of fully segregated streams. The method was further validated with carefully selected mechanistic micromixing models, and experimentally confirmed in studies using an in-line rotor–stator high-shear homogenizer. The results clearly demonstrate that the model accurately describes the course of the diazo-coupling reaction; it enables the correct determination of the contribution of by-products in the reactive mixture, which serves as a key indicator of local micromixing kinetics. The method introduced in this work, combined with CFD, will enable, in the near future, a comprehensive assessment of the integrated effects of convection and mixing at the macro-, meso-, and microscale in industrially relevant equipment.
