Experimental and Modeling Study of Micromixing Characteristics in a Stirred Tank Integrated with Annular Jet Flow

To enhance the micromixing in chemical processes, a jet-stirred tank reactor (JSTR) was developed by integrating an annular jet with the width of 0.38 mm and 0.60 mm into a 81 L stirred tank to provide localized energy intensification. The iodide–iodate reaction method was used to evaluate the micromixing performance under different operating and structural conditions. Results showed that the micromixing time determined by the incorporation model decreased with increasing impeller speed and jet width, while the feeding position and jet velocity can significantly influence the micromixing due to jet deflection. The micromixing time in the JSTR ranged from 10 to 30 ms, representing a reduction of up to 3.45 times compared with the situation that only stirred tank was used. Numerical simulations of flow in the JSTR revealed four typical flow patterns illustrating the way by which the jet can affect the micromixing within the reactor. Furthermore, an operating diagram for mapping the micromixing time based on energy dissipation rate analysis was developed.