Characteristics of newly formed child droplets in the collisions of slurry droplets with solid particles

The interaction of slurry droplets and solid particles is utilized in practical applications such as heat drying and the generation of multicomponent fuel sprays. The generation of aerosols and suspensions by spray drying is widely used in the food, chemical, pharmaceutical, cosmetic, fuel, and power industries. This research reports the experimental findings on the regimes and outcomes of the collisions of water-based slurry droplets with solid particles of the same material. The maps of two collision regimes (agglomeration and stretching separation) were plotted with the number and size of child droplets recorded in the coordinate system allowing for the Weber number and linear impact parameter. The key parameters of droplets and particles were varied: sizes and velocities, concentration of solid particles in droplets, and droplet shapes. The thickness of the residual liquid film on the particle surface was examined. Conditions of effective secondary atomization of droplets were identified. Mathematical equations with dimensionless parameters were derived to predict the conditions of transition to agglomeration and atomization of liquid droplets through collisions with solid particles.