Molecular Dynamics Simulation Of The Wettability Of Water Droplets Containing Organic Solvents And The Condensation Of Water Vapor

Surface wetting characteristics have a wide range of applications in water resistance,corrosion resistance,mechanical lubrication,and cleaning.Enhancing the surface’s superhydrophobicity can improve the condensation heat transfer,boiling heat transfer,and corrosion resistance of the surface.The excellent wetting characteristics of the lubricating oil are conducive to mechanical lubrication.In rainy weather,the wettability of the rearview mirror of the vehicle is enhanced to form a liquid film and improve the visibility,so the study of surface wetting characteristics is of great significance.Condensation is a physical phenomenon from microscopic to macroscopic.At present,people have studied more deeply about the macroscopic aspect of condensation.The intersection of energy and physical chemistry and other fields has made the research on condensation more oriented to the microscale direction.Therefore,this text studies and analyzes the wetting characteristics and coagulation process of the solid surface from the microscopic scale.Molecular dynamics method was used to study the wetting of droplets containing solvent on the solid wall.In the simulation,the solid wall surface uses silicon,carbon,silicon dioxide and hydroxylated surfaces with different hydrophilicities.By adding different mass fractions of organic solvents ethanol and ethylene glycol to the water droplets,the steady-state contact characteristics of the droplets on the solid surface and their variation with temperature were analyzed.Furthermore,molecular dynamics method was used to analyze and study the condensation process of water vapor on solid surfaces.The solid wall surface adopts different roughness and hydroxylated surfaces to study the effect of roughness and surface hydroxylation on water vapor condensation.Analysis of the condensation process on the solid surface and the effect of temperature on condensation by adding organic solvent ethanol with different mass fractions.It was found that among silicon,carbon,and silica surfaces with different hydrophilicity,the contact angle of the droplet on the silicon surface was the smallest,because the interaction between the silicon surface and the droplet was the largest.The wetting characteristics of hydroxylated surfaces are better than non-hydroxylated surfaces.The contact angle of the droplet on the solid surface decreases with the increase of the mass fraction of ethanol and ethylene glycol.The higher the temperature,the smaller the contact angle of the droplet with the solid surface.The difference in solid wall surface roughness affects the number of water molecules that can enter the column gap and does not affect the total amount of steam condensation.The hydroxylated surface is conducive to condensation,because the attraction of molecules to the hydroxylated surface is enhanced.With the increase of the number of ethanol molecules in the mixed steam,the number of condensed molecules increased.The higher ambient temperature enhances the wetting effect much less than the disadvantages of condensation.