Study On Droplet Impact Dynamics On Superhydrophobic Surface Based On Parallelogram Mechanism

Superhydrophobic surface has attracted many scholars because of its unique characteristics such as self-cleaning,anti-freezing and anti-fogging.However,the process of droplet collision on superhydrophobic surface is widely used in practical applications,such as self-cleaning,anti-freezing,corrosion protection and so on.Therefore,a comprehensive understanding of the process of droplet impact on superhydrophobic surface is of great significance in scientific research and practical production.However,the current research on the impact of droplets on the super-hydrophobic surface is mainly focused on the geometric parameters after high-speed imaging,and the understanding of the mechanical mechanism in the contact process is still insufficient.Due to the short contact time and small interaction force during droplet impact,the measurement of dynamic interaction force during droplet impact still faces great challenges.In previous studies,rectangular elastic beams with fixed ends or single ends are regarded as elastic elements,but the larger damping ratio of such elastic elements leads to greater accuracy loss in dynamic force measurement.Therefore,in this paper,a flexible hinge with low damping and high dynamic response is designed as an elastic element and used in combination with a high-speed camera to study the instantaneous dynamic characteristics of liquid drop impact.The research work of this paper is mainly divided into four parts.Firstly,Polydimethylsiloxane(PDMS)super hydrophobic surface with contact Angle of about152° was prepared by template casting.Secondly,Solidworks software was used to conduct 3d modeling of the prepared PDMS superhydrophobic substrate and Xflow fluid simulation software was used to conduct numerical simulation of the impact process of liquid drops,and the deformation changes of liquid drops in the surface columnar array were studied in depth.Thirdly,a flexible hinge with low damping and high dynamic response was designed,and on this basis,a measuring platform was built to simultaneously measure the droplet shape change and the droplet-base interaction force during impact.The platform realizes the measurement of droplet deformation at a frame rate of 10000 per second and the measurement of dynamic force with a precision of 0.05 mn.Finally,the dynamic characteristics of droplet collision were studied under different impact velocity,different substrate structure and different elastic materials,and the contact time,maximum spreading diameter and maximum impact force of droplet collision were analyzed and modeled.