Molecular Dynamics Simulation Of Liquid Boiling On Metal Surface

With the progress of computer technology and the continuous improvement of the relevant theories of molecular dynamics simulation,the application of molecular dynamics simulation methods to the study of the mechanism of boiling heat transfer can allow us to have a deeper understanding of the boiling heat transfer process at the micro and nano scale,because there are many inconveniences in exploring the heat transfer process at the micro and nano scale through experiments at this stage,therefore,in recent years,molecular dynamics simulation for boiling heat transfer has become the focus of heat transfer research at the micro and nano scale.In this paper,through molecular dynamics simulation,the boiling heat transfer characteristics of different surface structures and materials under the thickness of two liquid films are explored,the boiling heat transfer process of liquid films of different thicknesses on the solid metal wall and the liquid metal wall is simulated,the influence of the wall structure on the boiling phenomenon is analyzed,and the difference between the thermal vaporization phenomenon of the liquid film caused by the thickness of the liquid film is compared.In this paper,the phenomenon of boiling liquid film of two thicknesses on the planar substrate and the grid-type nanostructure substrate is simulated at first,and after simulation and comparison,it is found that the depression of the grid substrate is conducive to the accumulation of heat of the liquid,and the depression is more conducive to bubble nucleation than the planar substrate.Boiling occurs on the grid substrate earlier,and the average heat flow between the grid substrate and the liquid film is greater before boiling.After simulating and comparing the boiling phenomenon of liquid film of different thicknesses,it is found that the improvement of heat transfer efficiency between the substrate and the liquid film has a significant impact on the temperature of the liquid near the substrate,which is conducive to the rapid heat absorption and vaporization of the liquid near the substrate and the relatively thin liquid film,and in the case of thick liquid film,the vapor layer between the liquid film and the substrate will have a negative impact on heat transfer.Secondly,the molecular dynamics simulation of the liquid film boiling phenomenon on the surface of gallium metal is carried out,and the gallium metal is in the liquid state,which is different from the common solid metal wall,and the gallium atom has a higher degree of freedom of motion.The boiling phenomenon observed in the initial stage of the boiling process and the planar solid substrate is close,and then transformed into a boiling phenomenon that is more intense than the grid solid substrate,and the data obtained from the analysis find that the heat transfer heat flow between the liquid metal substrate and the liquid film is close to the initial stage of boiling and the planar substrate,and then rises to a level higher than the grid substrate.After investigation,it was found that the reason for this phenomenon was that due to the process of bubble generation and rupture,there were irregular ups and downs and fluctuations on the initially relatively smooth liquid metal surface,and the contact surface of this irregular liquid and the wall surface changed the law of bubble nucleation,so that the phenomenon of boiling process was transformed into a boiling phenomenon similar to that on a grid-type substrate.In addition to summarizing the above conclusions,this paper also combines the phenomenon snapshots at different times to describe the boiling process obtained by simulation in detail,calculates the average temperature change curve of liquid film near the wall,makes a cloud map of atomic Kinetic energy distribution at different times according to the simulated data,analyzes the average heat flow in each time period,comprehensively analyzes the calculated data and existing related theories,and makes a reasonable explanation and explanation of different phenomena that occur at each stage.