Experimental study and numerical simulation of liquid–liquid dispersions in micro-impinging jet mixers

Abstract

This study investigates the turbulent two-phase dispersion of toluene-water in micro-impinging jet (MIJ) mixers using both experimental and numerical methods. We employ computational fluid dynamics combined with the population balance model (CFD-PBM) to predict the mean droplet size (d₃₂) and droplet size distribution (DSD). The numerical predictions align well with the experimental results. The liquid–liquid dispersion in the MIJ mixer is a two-step process, each step governed by the velocity ratio (r) and Reynolds number (Re_j), respectively. By increasing the volume flow rate (Q) and r, or by reducing the diameter of the outlet orifice of mixing chamber (D_o), the dispersion process can be intensified. This leads to the production of smaller droplets with a narrow DSD within a millisecond timeframe. Additionally, we propose a correlation for d₃₂ that accurately describes the two-step dispersion process of the mixer, providing a reliable guide for the design and optimization of liquid–liquid systems.