The collision between the nanoparticle and wall surface is supposed to cause the escape of nanoparticle molecules which indicates the potential phase change of the nanoparticle.It is significant to understand the mech...The collision between the nanoparticle and wall surface is supposed to cause the escape of nanoparticle molecules which indicates the potential phase change of the nanoparticle.It is significant to understand the mechanism of the collision process involved with phase change for applications of nanoparticles in energy and mass transfer.In this study,the collision process between nanoparticle made of monatomic argon molecule and wall surface made of nickel metal crystal is simulated by molecular dynamics method.The travelling behavior and energy transformation of escaped molecules are respectively analyzed.The effects of the intermolecular force and initial temperature on the collision process are further discussed.The results show that the nanoparticle can be accelerated by the wall surface with the intermolecular force and finally collide with it.The molecules escape from the nanoparticle either by bouncing off the wall surface or the intermolecular energy exchange with the energy transformation between the potential energy and kinetic energy.The molecules far from the nanoparticle center are more likely to escape,while the velocity distributions of the escaped molecules follow the Maxwell distribution.More escaped molecules,namely higher phase change potential,are observed with lower intermolecular force and higher initial temperature.As a fundamental study on nanoparticle phase change in the vicinity of wall surface,the present investigation will be helpful for further study on the heat transfer characteristics and phase change mechanisms of nanoparticles.展开更多
基金National Natural Science Foundation of China(Grant No.51776002)the support from Beijing Engineering Research Center of City Heat are gratefully acknowledged。
文摘The collision between the nanoparticle and wall surface is supposed to cause the escape of nanoparticle molecules which indicates the potential phase change of the nanoparticle.It is significant to understand the mechanism of the collision process involved with phase change for applications of nanoparticles in energy and mass transfer.In this study,the collision process between nanoparticle made of monatomic argon molecule and wall surface made of nickel metal crystal is simulated by molecular dynamics method.The travelling behavior and energy transformation of escaped molecules are respectively analyzed.The effects of the intermolecular force and initial temperature on the collision process are further discussed.The results show that the nanoparticle can be accelerated by the wall surface with the intermolecular force and finally collide with it.The molecules escape from the nanoparticle either by bouncing off the wall surface or the intermolecular energy exchange with the energy transformation between the potential energy and kinetic energy.The molecules far from the nanoparticle center are more likely to escape,while the velocity distributions of the escaped molecules follow the Maxwell distribution.More escaped molecules,namely higher phase change potential,are observed with lower intermolecular force and higher initial temperature.As a fundamental study on nanoparticle phase change in the vicinity of wall surface,the present investigation will be helpful for further study on the heat transfer characteristics and phase change mechanisms of nanoparticles.
