A coupled coalescence model considering the effect of the surface deformation before and after droplet collision

The deformation and collision of droplets in turbulent dispersion systems significantly affect droplet coalescence. However, existing coalescence models have not reasonably accounted for these factors, leading to inaccurate predictions of droplet size distribution. In this work, an improved model was developed by coupling the surface deformation of two droplets before collision with the squeezing deformation during the collision process. The deformation of the droplet before collision was obtained based on the conversion relationship between eddy kinetic energy and droplet surface energy. Furthermore, the effect of deformation induced by collisions was evaluated based on the centroid offset during droplet collisions. This model incorporates the effect of droplet deformation before collision on the collision probability of droplets. It was found that the improved model can better describe the deformation characteristics of droplets before collision, and the predicted coalescence rate and droplet size distribution are both in good agreement with experimental results.