Droplet size distribution in annular flow affected by the breakup and coalescence processes

Abstract

The present work studies the influence of droplet breakup and coalescence processes on droplet size distribution in annular flow. The influence of the breakup and coalescence processes on droplet number is reflected in four factors, i.e., breakup-induced droplet birth, breakup-induced droplet death, coalescence-induced droplet birth and coalescence-induced droplet death. The four effects jointly shape the probability density distribution of the droplet size after reaching a dynamic equilibrium. A numerical procedure is compiled using the microscopic mechanisms of the droplet breakup and coalescence process to calculate the droplet size distribution and characteristic droplet sizes. The numerical predictions are fully validated by comparison with the experimental data available in the literature. In addition, the birth and death of droplets in the breakup and coalescence processes are discussed in detail.