Mechanism Research Of Liquid Anti-impalment Superwetting Mesh And Its Application

Droplet impact meshes are universal and important,and play an important role in nature and human society,especially in the fields of basic science,industry and agriculture,which can solve agricultural irrigation,gas-liquid mass transfer and separation,inkjet printing and chemical protection and other key issues.In the past 20 years,based on the development of superwetting surface interface,the impact phenomenon of droplets impact superwetting meshes has been widely studied,but there are still many problems to be solved.Among them,most of the studies focus on the capillary penetration threshold of low-velocity droplets impinging on superwetting meshes,and there are only sporadic reports on the energy conversion analysis after droplet impingement.Especially in the application research of droplets impinging on porous meshes.Compared with promoting droplet dispersion,it is a big problem to retain the permeability of porous mesh and make it resist high-speed droplet penetration.It is also a key issue in the application of waterproof and breathable materials.On this basis,thesis analyzes the impact behavior of droplets impinging on superwetting meshes from the perspective of dynamics and energy conversion.A dual-layer synergistic strategy to resist the impact of continuous high-speed droplets is proposed,and its application value in the field of waterproof and breathable is verified.The main research contents of this paper are as follows:（1）Droplet impact on a monolayer superwetted mesh surface.A high-speed camera was used to capture the impact behavior of droplets on three super-wetting（SHPi,SHPo,and Janus）mesh surfaces in two dimensions,and the impact dynamics and energy conversion were theoretically analyzed.And further discuss the relationship between the impact behavior of the three superwetting meshes and the droplet impact velocity and mesh size,making it a theoretical basis for anti-droplet penetration research.（2）Droplet impact double-layer synergistic mesh analysis and its application.Thesis,a novel double-layer synergistic mesh that can resist the impact of continuous high-speed droplets is proposed,and the synergistic mesh is theoretically proved to have a double waterproof mechanism.That is,the instantaneous penetration mechanism of the bottom mesh blocking high-speed droplets and the long-term penetration mechanism of the stable liquid film blocking continuous liquid.Among them,the influence factors such as the wettability composition,mesh spacing,mesh size and droplet size of the double-layer mesh are analyzed.It is concluded that the dry SHPi+Janus mesh can resist 2.68 m/s droplet puncture with a diameter of 2.6 mm.And when the impact velocity reaches 3.5m/s,the penetration mass of the droplet is only 3.6%,while the penetration rate of the control mesh is 61.1%.At the same time,an inclined impact test was carried out on the double-layer mesh.It is concluded that the SHPi+Janus mesh placed at an inclination of60° can resist 4.08 m/s droplet puncture with a diameter of 2.6 mm.It shows that the double-layer collaborative mesh has wider application value.Finally,the feasibility of its application in waterproof and breathable screen windows is verified by simulating continuous droplets impacting the double-layer synergistic mesh.