Numerical study of droplet fragmentation during impact on mesh screens
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When a high-speed droplet impacts on mesh screens, part of the droplet penetrates the screen through its pores and generates smaller secondary drops, which spray downstream in a conical distribution. This instantaneous phase fragmentation phenomenon has been widely utilized in liquid spray applications and multiple-phase liquid separation. During droplet deformation, the intense liquid–gas fragmentation can lead to high nonequilibrium effect, which makes it hard to simulate by traditional fluid computational method. In this study, for the first time, we provided a numerical method to simulate the entire process of penetration dynamic behaviors. This 3D droplet-impact model based on MDPD (many-body dissipative particle dynamics) method exhibits high stability. A special solid–liquid boundary condition was proposed and successfully reduced the massive computational resources wasted on the solid mesh surface. To verify our model, the impacting of a droplet on a flat surface and on a mesh screen were simulated, respectively. The result showed a good match with our previous drop impact study and our experiment of the whole process about a droplet fragmented into hundreds of small drops. We further studied the mass transfer ratio (the ratio of penetrated drops to the initial droplet) and the ejection angle (the angle of the spray cone). The mass transfer ratio and ejection angle can be approximated as a function of Weber number, solid fraction and mesh number by summarizing the regular drop-penetrated behaviors over initial speed and mesh number.
This work was supported by the National Key R&D Program of China (Grant No. 2017YFC0111100, 2016YFC1100300), National Natural Science Foundation of China (Grant No.11972215) and National Numerical Windtunnel Project (Grant No. NNW2019ZT2-B05).
- Plimpton S, Crozier P, Thompson A (2007) LAMMPS-large-scale atomic/molecular massively parallel simulator. Sandia Natl Lab 18:43Google Scholar
- Wang F, Yang L, Wang L, Zhu Y, Fang T (2019) Maximum spread of droplet impacting onto solid surfaces with different wettabilities: adopting a rim-lamella shape. Langmuir, NYGoogle Scholar
- Zhang R, Hao P, He F (2016a) Rapid bouncing of high-speed drops on hydrophobic surfaces with microcavities, vol 32. Langmuir, NY, pp 9967–9974Google Scholar
- Zhang R, Hao P, He F (2017) Drop impact on oblique superhydrophobic surfaces with two-tier roughness, vol 33. Langmuir, NY, pp 3556–3567Google Scholar
- Zhang K, Li Z, Maxey M, Chen S, Karniadakis GE (2019) Self-cleaning of hydrophobic rough surfaces by coalescence-induced wetting transition, vol 35. Langmuir, NY, pp 2431–2442Google Scholar