Study on the dynamic behaviors of collision and coalescence of binary double low-viscosity droplets

The volume of fluid method is used to track the phase interface changes while analyzing and investigating the horizontal collision behavior of binary low-viscosity droplets. The result shows that the droplets with different particle size ratios and relative velocity will have three kinds of collision results: coalescence, reflexive separation, and stretch separation when the collision angle is 0, and there is no bounce phenomenon. The kinetic energy of droplets with a large particle size ratio and relative velocity decreases faster after collision, the surface energy decreases slowly, and the energy is dissipated the most. The influence of temperature and humidity on colliding results is analyzed for the first time, and it is found that the influence is negligible. The critical Weber numbers of coalescence-reflexive separation and coalescence-stretch separation after the collision of two droplets of equal size are 22.09 and 38.74, respectively. The existing low-viscosity droplet collision transition boundary curve is modified for the first time. A new droplet collision model considering viscous dissipation is established under the interaction of particle size ratio and relative velocity.