摘要
目的研究液滴在斜锥表面的定向流动特性,揭示液滴在斜锥表面的定向输运机理。方法以斜锥表面液滴运动行为为研究对象,通过数值模拟技术提取液滴动力学参数,探讨不同斜锥结构参数对液滴自输运行为的影响。结果液体内部速度的不均匀分布导致液滴内部产生速度涡旋,在泰勒毛细升力的作用下,斜锥间隙产生了涡量较大的速度主涡旋,液滴内部产生了涡量较小的速度次涡旋。在液滴定向输运过程中,2种涡旋的旋转方向与液滴的输运方向保持一致。液滴自输运过程伴随着表面能、动能的相互转化。在铺展收缩阶段,液滴的形变量较大,固–液接触面积和液滴的表面能先增大再减小,液滴运动速度却先减小再增大。在稳定输运阶段,液滴的表面能和速度基本保持不变。泰勒毛细升力和斜锥间隙中的不平衡毛细力驱使液体不断填充斜锥间隙。液滴在斜锥表面受到不平衡的钉扎阻力,使得液滴左侧更易脱钉,保证整个液滴向右无损输运。结论可为揭示液滴在斜锥表面的流动特性和自输运机理提供理论支持,指导研制以斜锥结构为仿生原型的机械功能表面。
The directional flow characteristics of droplets on the inclined cone surface were studied to reveal the directional transport mechanism of droplets on the inclined cone surface.This article focuses on the motion behavior of droplets on the inclined cone surfaces.By using numerical simulation technology to extract droplet dynamics parameter data,the influence of different inclined cone structural parameters on droplet self-transport behavior were explored.The research found that the uneven distribution of fluid velocity within the liquid lead to the generation of velocity vortices within the droplet.Under the action of Taylor capillary rise,a main velocity vortex with a higher vorticity value was generated in the inclined cone gap,and a velocity secondary vortex with a lower vorticity value was generated inside the droplet.During the directional transport of droplets,the rotation direction of the main and secondary vortexes remained consistent with the transport direction of the droplet.And the self-transport process of the droplet was also accompanied by the mutual conversion of the surface energy andkinetic energy.During the expansion and contraction stages,the droplet underwent significant deformation,and the solid-liquid contact area first increased and then decreased.The surface energy of the droplet also increased and then decreased,but the movement speed of the droplet first decreased and then increased.During the stable transmission stage,the surface energy and velocity of the droplets remained basically unchanged.The Taylor capillary rising and the imbalanced capillary force in the inclined cone gap drove the liquid to continuously fill the inclined cone gap.The unbalanced pinning resistance of the droplet on the inclined conical surface made it easier for the left side of the droplet to separate,ensuring that the entire droplet was transported to the right side without damage.The liquid droplet was subjected to the combined action of unbalanced capillary force and Taylor capillary rise on the surface of the inclined cone,resulting in the formation of velocity vortexes inside the liquid,prompting the fluid to fill the wedge-shaped space between the inclined cones.The nailing force on the left and right sides of the droplet was different,and the left side of the droplet was more prone to detachment,which also ensured that the droplet moved to the right as a hemispherical whole.And the self-transport process of the droplet was accompanied by the mutual conversion of surface energy and kinetic energy.When the shape variation of the droplet was large,the solid-liquid contact area first increased and then decreased,and the surface energy of the droplet also increased and then decreased.However,the velocity of the droplet movement first decreased and then increased.When the deformation of the droplet reached a stable state,the surface energy and velocity of the droplet remained basically unchanged.This study provides theoretical support for revealing the flow characteristics and self-transport mechanism of liquid droplets on the inclined cone surface,and is used to guide the development of mechanical functional surfaces using the inclined cone structure as a biomimetic prototype.
作者
张国涛
马亮亮
童宝宏
梁方玲
王孝义
ZHANG Guo-tao;MA Liang-liang;TONG Bao-hong;LIANG Fang-ling;WANG Xiao-yi(School of Mechanical Engineering,Anhui University of Technology,Anhui Maanshan 243000,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2023年第12期428-439,共12页
Surface Technology
基金
国家自然科学基金(52005005,51975005)
特殊服役环境的智能装备制造国际科技合作基地开放基金(ISTC2021KF06,ISTC2022KF02)。
关键词
斜锥表面
液滴自输运
表面能
不平衡毛细力
泰勒毛细升
钉扎力
inclined cone surface
droplet self-transport
surface energy
unbalanced capillary force
Taylor capillary
pinning force
