A new method to quantify droplet size distribution based on Monte Carlo simulation in liquid-liquid solvent extraction

The diameter of a dispersed-phase droplet determines the interfacial area in liquid-liquid solvent extraction. Capturing the polydispersity of a liquid-liquid flow is crucial in computational fluid dynamics. In this study, a droplet size probability (DSP) model applied to the Eulerian-Eulerian (E-E) framework is proposed to characterize the droplet size distribution (DSD) at mesoscale. The physical characteristic of the DSP model demonstrates size similarity between the computational cells and droplets. Following the single-droplet hypothesis, two sub-models are investigated. The first model is the distribution function of the droplet size, and the second model is Monte Carlo simulation in the computational domain. By sampling randomly from the probability density function of the DSD, the loss of physical information caused by the averaging procedure is avoided. Simulation results of the pulsed disc and doughnut column (PDDC) showed that the CFD-DSP coupled model accurately predicted the dispersed-phase holdup and DSD under various conditions.