Molecular Dynamics Simulation Of Water Vapor Nucleation/Growth Processes

Water,playing an important role in heat transfer,heat storage and other efforts,is extensive and significant for applications in refrigeration power generation,aerospace and other fields.Its dynamic behavior,such as phase change,heat transfer and dissolution,has been an important subject of scientific research.Many researchers have conducted a lot of experimental and theoretical research,however,all of the present results are still not enough to explain all the micro-mechanism of condensation and phase transformation.In this study we simulated the process of condensation of water vapor by molecular dynamics techniques.The factors that affect the process(such as size,pressure,the impact of other substances)were analyzed to help researchers better understand the microcosmic mechanism of condensation.Finally,the solubility of the non-condensable gas under high pressure was modeled to provide more theoretical support for engineering applications.The main research results are summarized as follows:The nucleation and monomer growth of the condensation were modeled under different pressure and temperature.After the total heat energy of the cold source and heat source during the whole simulation process and the total energy state of the model was recorded and average condensation heat transfer during the simulation,compared the heat transfer and mass transfer of different droplet diameters in the process of nucleation was calculated,we found the simulation results show that the heat transfer coefficient of the condensation phase transition is much higher than that of the macroscopic experimental data during the nucleation and monomer growth of the condensation.The effect of the condensation rate increases with the diameter of the droplet.Optimized the parameters of oxygen and nitrogen and the correctness of the optimization results were verified by comparing the thermodynamic properties such as thermal conductivity or gas-liquid density and saturation pressure and temperature.And then simulated the heat transfer and mass transfer during the nucleation and condensation of two kinds of non-condensable gases(oxygen and nitrogen)at the initial stage of solidification and solidification.The results show that the higher the coagulation rate is,the more the condensing rate is,and the rate of oxygen condensation decreases as the oxygen content increases too much.Besides The influence of pressure on the condensation transformation is further analyzed.It is found that the higher pressure,the faster the velocity is,and there is a linear relationship between the pressure and the coagulation rate.Finally,the solubility and dissolution characteristics of oxygen in pure water at different temperatures were simulated.The parameters such as the number of dissolved oxygen molecules and the model pressure were analyzed,and compared with the experimental and fitting results.Through the above research,we hope to provide the researchers with more understanding of the microcosmic mechanism of the nucleation and the growth process of the coagulation phenomenon,and improve the phase change efficiency.At the same time,by simulating the solubility of the non-condensable gas under high pressure conditions,More theoretical support.