(152b) Modeling Coalescence and Breakup By Combining Computational Chemistry and Fluid Dynamics

Coalescence and breakup of droplets and bubbles are fundamental processes in multiphase fluid dynamics, playing critical roles in applications like emulsification, drug delivery, and chemical engineering. Simulating these phenomenas require accurate modeling of intermolecular forces, surface tension, and the dynamic balance between cohesive and disruptive forces acting on the droplets or bubbles. Computational Chemistry (CC) simulations offer a powerful tool to study droplet coalescence and breakup at the molecular level, capturing the interactions of individual molecules and providing detailed insights into how interfacial properties influence macroscopic behavior. By fitting model parameters such as surface tension, viscosity, and interaction forces to CC data, predictive models for droplet behavior can be developed with enhanced accuracy reducing the number of expensive and time consuming experimental investigations. These models can then be applied in Computational Fluid Dynamics (CFD) simulations to study full-scale apparatuses, providing a bridge
between molecular interactions and observable multiphase flow behavior.

At the AIChE Spring meeting 2025 we have presented a proof-of-concept how CC and CFD can be combined to model such systems. In this contribution we will validate our previous work based on an experimentally well investigated water/toluene system: CC results are used to fit model parameter of different existing coalescence and break-up models. These models are then used in a 3D CFD simulation of a mixing tank to predict the final size distribution.