## 3 Results and Discussion
### Effect of Interfacial Tension of Liquid  
The impact of the interfacial tension of liquid on the characteristics of droplet-particle collisions can be explored for multicomponent compositions. In the atomization of such liquid droplets, not only the internal forces of inertia, but also the molecular bonds contribute greatly to the occurrence of stretching separation. The higher the interfacial tension, the stronger the molecular bonds [45]. Industrial plants, normally using multicomponent liquids, should provide the conditions (by varying the interfacial tension in the given ranges) when stretching separation dominates. This would increase the area of liquid spraying and reduce the average size of liquid fragments. The images demonstrating the effect of the liquid interfacial tension on the characteristics of droplet-particle collisions are presented in Figure 8 and in Video S3. Figure 7: Collision regime maps for liquid droplets interacting with solid particles (**a**) and ratios of free surface areas after (\(S_{1}\)) and before (\(S_{0}\)) the head-on collision with \(B=0\) (**b**) at varying liquid surface tensions: 1—distilled water; 2—0.5 vol% Tween-20 and 95.5 vol% water; 3—0.5 vol% Tween-80 and 95.5 vol% water; 4—0.5 vol% neonol and 95.5 vol% water. [PERSON] et al. [45] studied the patterns of collisions of liquid droplets with each other at variable rheological properties. It was established [45] that a decrease in the interfacial tension contributes to smaller sizes of internal water droplets in the diesel fuel layers, which makes the emulsion more homogeneous. It is believed that in the collision of diesel emulsion droplets with a solid particle when the liquid contains 0.8-1.6 g/L emulsifier, this effect contributes to a reduction in the child droplet size by up to 30% compared to water. The child droplet number here increases. For example, for diesel emulsion droplets (10 vol% diesel, 90 vol% water) without an emulsifier, there are five child droplets. For emulsion droplets with 1.6 g/L emulsifier, their number reaches 15 at identical initial velocities and sizes of droplets. The greatest shift in the transition boundaries between stretching separation and agglomeration was recorded (Figure 9a) for droplets of the diesel emulsion with an emulsifier D\({}_{\text{c}}\)D (1.6 g/L). This is because D\({}_{\text{c}}\)D increases the stability of the emulsion (i.e., reduces delamination) [45], strengthening the molecular bonds. Lower inertia forces, thus, lower transient Weber numbers are required to break up such emulsion. A high concentration of an emulsifier significantly reduces the surface tension at the liquid-air and liquid-liquid interface. This means that less energy is necessary for the deformation of specific surfaces on both interfaces. Thus, less kinetic energy (Figure 9a) and lower Weber numbers will be required for the liquid droplet dispersion. The comparison of regime maps of diesel fuel emulsions and distilled water reveals a 20-40% decrease in the critical Weber number for the occurrence of stretching separation within the whole range of \(B\). The experiments established that the interfacial tension of liquid has a modest impact on the duration of the droplet spreading over the particle surface, and thus on the spreading rates. For instance, with a decrease in the liquid interfacial tension from 0.04257 to 0.00341 N/m, the droplet spreading time decreases by only 4-7%. Figure 8: Images illustrating the collisions of water droplets with a particle in stretching separation regime at varying interfacial tensions of liquid. Figure 9b shows a major impact of the interfacial tension of liquid on the ratio of \(S_{1}\) to \(S_{0}\) as a result of its interaction with a solid particle. At minimum interfacial tension, the number of newly formed fragments was found to be maximum. Thus, the \(S_{1}/S_{0}\) ratio increased. Such pattern is observed within the whole Weber number range under study.