Numerical investigation of air cushioning in the impact of micro-droplet under electrostatic fields

Tian, Yu1; Di, Linsen1; Lai, Wuxing1; Guan, Yin2; Deng, Weiwei3; Huang, YongAn1

2023

10.1063/5.0134281

PHYSICS OF FLUIDS   影响因子和分区

1070-6631

1089-7666

Air cushioning widely occurs when a droplet impacts onto a solid or fluid surface at low velocity, which is mediated by the lubrication pressure of a thin air layer. Such air cushioning phenomena for micro-sized droplets bear important implications for precision coating and inkjet printing. In this study, we investigate numerically the air cushioning in the micro-sized droplets of various sizes impacting on a solid surface based on the volume of fluid method as implemented in the OpenFOAM framework. We find that the critical impact speed for bouncing on the air cushion increases as the droplet radius decreases, while the Weber number remains in a narrow range from 1 to 4. The scaling law of the critical impact speed for bouncing is derived by balancing the lubrication pressure of the air cushion with the capillary pressure and droplet inertia. The impact mode transforms from bouncing to wetting with an electric field. A group of phase diagrams of the electric Bond number vs the Weber number is presented for various droplet sizes. The diagrams are consistent with the scaling law of the critical electric field for the wetting-without-bubble mode. The findings provide insights for applications based on micro-droplet deposition, such as inkjet/electrohydrodynamic printing and spray coating, to avoid the adverse effect of air cushioning or air entrapment.

SCI ; EI

英语

其他

National Key Research and Development Program of China[2021YFB3200700] ; National Natural Science Foundation of China["11932009","52175536"] ; Natural Science Foundation of Hubei Province[2020CFA028]

Mechanics ; Physics

Mechanics ; Physics, Fluids & Plasmas

WOS:000922189400006

AIP Publishing

20230513474306

Air ; Air cushioning ; Coatings ; Drops ; Electric fields

Rolling Stock Equipment and Components:682.2 ; Electricity: Basic Concepts and Phenomena:701.1 ; Chemical Products Generally:804 ; Coating Materials:813.2

PHYSICS

Web of Science

1.Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Wuhan 430074, Peoples R China
2.Huazhong Univ Sci & Technol, Sch Energy & Power Engn, Wuhan 430074, Peoples R China
3.Southern Univ Sci & Technol, Dept Mech & Aerosp Engn, Shenzhen 518055, Peoples R China

Tian, Yu,Di, Linsen,Lai, Wuxing,et al. Numerical investigation of air cushioning in the impact of micro-droplet under electrostatic fields[J]. PHYSICS OF FLUIDS,2023,35(1).

Tian, Yu,Di, Linsen,Lai, Wuxing,Guan, Yin,Deng, Weiwei,&Huang, YongAn.(2023).Numerical investigation of air cushioning in the impact of micro-droplet under electrostatic fields.PHYSICS OF FLUIDS,35(1).

Tian, Yu,et al."Numerical investigation of air cushioning in the impact of micro-droplet under electrostatic fields".PHYSICS OF FLUIDS 35.1(2023).