Numerical Simulation Research On Droplet Bounce Based On Lattice Boltzmann Method

The phenomenon of multiphase flow has important reference and guiding significance for our life and production.It has broad application prospects in energy development and storage,life science research and exploration,and material preparation and application.The bounce phenomenon of droplets in multiphase flow is most closely related to our lives,such as printing,spraying,and self-cleaning.The research of droplet bouncing phenomenon has achieved fruitful results at home and abroad,but there are still many fields that have not been studied and explored in depth,especially the quantitative analysis of droplet bouncing phenomenon is relatively small,and the droplet micro-scale.Many harsh conditions,such as rapid changes and easy deformation,have brought great challenges to the in-depth study of the droplet bounce phenomenon,which limits people's understanding of the droplet bounce phenomenon to a certain extent,and hinders the droplet bounce phenomenon.Application in life production.In recent years,the numerical simulation method based on lattice Boltzmann has been favored by scholars.This method has simple algorithm,easy programming,small memory required,high parallelism,easy to handle complex geometric boundaries,and timely tracking of dynamic changes between phases.It is especially suitable for Study the dynamic change process of tiny droplets.For this reason,this paper adopts the numerical simulation method based on the lattice Boltzmann to conduct in-depth and detailed research on the droplet bouncing phenomenon.The main research contents are as follows:(1).A droplet bouncing mechanism model based on the chemical potential lattice Boltzmann method is established.This model uses chemical potential to calculate non-ideal forces,avoids the complicated process of calculating pressure tensor and tensor divergence,and greatly improves the efficiency of numerical calculations.On the basis of this modeling,a large density ratio model is also introduced,combined with the boundary conditions of chemical potential wetting,which improves the flexibility and accuracy of the model.At the same time,the model is also highly efficient and robust,providing a more robust model environment for accurately simulating the phenomenon of droplet bouncing.(2).Use this model to quantitatively study the droplet's bounce height,lateral bounce distance,flight time,internal momentum modulus change and rebound ability of the droplet.Experiments show that the rebound behavior of droplets depends on the degree of hydrophobicity and heterogeneity of the surface.When the droplet hits a uniform surface,the droplet rebounds to a certain height from the vertical substrate,and the bounce height increases with the increase of the hydrophobicity of the surface.When the droplet hits the heterogeneous surface of two different components,the droplet rebounds laterally to the side with lower hydrophobicity.Through a large number of experimental studies,it is found that the droplet bounce phenomenon is related to the degree of surface chemical isomerization,and there is a certain quantitative relationship between the droplet bounce height and flight time and the surface contact angle.Through numerical simulation research,the understanding of droplet rebound mechanism has been deepened.(3).The mechanical mechanism analysis of the droplet bouncing phenomenon on homogeneous and chemically heterogeneous surfaces is carried out.The dynamic contact angle,contact line and unbalanced Young's force changes of the droplets are studied.Through a series of numerical simulation studies,the reasons for the bounce phenomenon of chemically heterogeneous surface droplets are revealed.Studies have shown that the lateral bouncing of droplets on chemically heterogeneous surfaces is caused by the asymmetric and unbalanced Young's forces on both sides.In summary,this paper uses the lattice Boltzmann method based on chemical potential to study the droplet mechanism change behavior in depth.This research promotes the understanding of the rebound mechanism of droplets hitting chemically heterogeneous surfaces,and provides a guiding strategy for accurately controlling the lateral bouncing behavior of rebounding droplets through hydrophobic and heterogeneous surfaces.