摘要
基于VOF(volume of fluid)方法,建立了重力条件下悬滴与卧滴在空气中合并过程的理论模型,并进行数值模拟,研究了悬滴与卧滴的合并流型,并分析了不同Bond数下悬滴与卧滴的合并动力学行为.结果表明,悬滴与卧滴接触后,液滴间形成的液桥在表面张力的作用下快速扩展,在液桥与针头间出现颈缩现象;悬滴与卧滴合并过程存在"合并无断裂"和"合并后断裂"2种合并流型,当Bond数约为0.05时,合并流型由无断裂向断裂转变.随着Bond数增大,液滴合并后断裂的无量纲时间随之减小,当Bond数大于0.18,液滴合并后断裂的无量纲时间逐渐趋向定值.
A theoretical model of the coalescence process of pendent and sessile droplets via VOF （ volume of fluid） method is developed and numerically analyzed to investigate the flow regime evo- lution and hydrodynamics of droplet coalescence under the gravity in air, particularly the droplet coalescence behaviors under different Bond numbers. The result indicates that, due to the surface ten- sion, a liquid bridge forms and quickly expands when two kinds of droplets contact, and the neck appears and shrinks between the liquid bridge and needle tip. Two coalescence flow patterns, ＂coa- lescence with no pinch-off＂ and ＂coalescence with pinch-off＂, are observed under different Bond numbers. The flow pattern changes from ＂coalescence with no pinch-off＂ into ＂coalescence with pinch-off＂ when Bond number is approximately 0.05. The dimensionless pinch-off time decreases with the rising Bond number and it turns to be constant if the Bond number is larger than 0.18.
出处
《东南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第1期74-78,共5页
Journal of Southeast University：Natural Science Edition
基金
国家自然科学基金资助项目(51222605
11190015)
江苏省杰出青年基金资助项目(BK20130009)
关键词
液滴
合并
流型
颈部断裂
droplet
coalescence
flow pattern
neck pinch-off
