Based on the lattice Boltzmann method（LBM）,an improved pseudo-potential model,combined with a method of adding force term,is used to simulate the two-phase flows caused by a liquid droplet impacting on a liquid film...Based on the lattice Boltzmann method（LBM）,an improved pseudo-potential model,combined with a method of adding force term,is used to simulate the two-phase flows caused by a liquid droplet impacting on a liquid film.In this model,the different phases are treated as one fluid,and the interfaces between the vapor and liquid phases can be obtained by density value of the fluid.This variant of the LBM allows one to obtain the densities of vapor and liquid with high accuracy.The model is validated by an example of phase separation.The early stage of the impact of droplet on liquid film is simulated,and the results are qualitatively consistent with physical phenomena.展开更多
Sedimentation in dilute suspensions of charged particles with thin double layers was investigated. The study covered sedimentation in polydisperse systems at a large Péclet number. The pair-distribution equation...Sedimentation in dilute suspensions of charged particles with thin double layers was investigated. The study covered sedimentation in polydisperse systems at a large Péclet number. The pair-distribution equation was solved by a regular perturbation method, and it was found that generally speaking the sedimentation coefficient deviates slightly from that at the infinitely large Péclet number except that the double layer was very thin. The results were found to pos- sess much more diversities than the case of hard spheres.展开更多
Soil interparticle forces can pose important effects on soil aggregate stability and rainfall splash erosion.Meanwhile,these interparticle forces are strongly influenced by specific ion effects.In this study,we applie...Soil interparticle forces can pose important effects on soil aggregate stability and rainfall splash erosion.Meanwhile,these interparticle forces are strongly influenced by specific ion effects.In this study,we applied three monovalent cations(Li^(+),Na^(+),and K^(+))with various concentrations to investigate the influence of specific ion effects on aggregate stability and splash erosion via pipette and rainfall simulation methods.The specific ion effects on soil interparticle forces were quantitatively evaluated by introducing cationic non-classical polarization.The results showed that aggregate stability and splash erosion had strong ion specificity.Aggregate breaking strength and splash erosion rate at the same salt concentration followed the sequence as Li^(+)>Na^(+)>K^(+).With decreasing salt concentration,the difference in aggregate breaking strength or splash erosion rate between different cation systems increased initially(1–10^(-2)mol L^(–1))and later was nearly invariable(10^(–2)–10^(–4)mol L^(–1)).The experimental results were well quantitatively explained by soil interparticle forces considering cationic non-classical polarization.Furthermore,both aggregate breaking strength and splash erosion rate of three cations revealed a strong positive linear relation with net force subjected to cationic non-classical polarization(R^(2)=0.81,R^(2)=0.81).These results demonstrated that different non-classical polarization of cations resulted in different soil interparticle forces,and thus led to differences in aggregate stability and splash erosion.Our study provides valuable information to deeply understand the mechanisms of rainfall splash erosion.展开更多
In the present work two component dense semiclassical plasma of protons and electrons is considered.Microscopic and electrodynamic properties of the plasma by molecular dynamic simulation are investigated.For these pu...In the present work two component dense semiclassical plasma of protons and electrons is considered.Microscopic and electrodynamic properties of the plasma by molecular dynamic simulation are investigated.For these purposes semiclassical interparticle potential which takes into account quantum mechanical diffraction and symmetry effects is used.The considered range of density of plasma is n=1022cm^(−3)to n=1024cm^(−3).Fluctuations and dynamic dielectric functions were calculated using velocity autocorrelation functions.展开更多
In this paper, the lattice-Bohzmann method is used to investigate the droplet dynamics after impact on horizontal and inclined solid surface. The two-phase interparticle potential model is employed. The model is found...In this paper, the lattice-Bohzmann method is used to investigate the droplet dynamics after impact on horizontal and inclined solid surface. The two-phase interparticle potential model is employed. The model is found to possess a linear relation between the macroscopic properties （ surface tension σ and contact angle α） and microscopic parameters （ G, G, ）. The flow state of the droplet on the surface is analyzed in detail, and the effects of surface characteristic, impact velocity, impact angle, the viscosity and surface tension of the liquid are investigated, respectively. It is shown that the lattice-Bohzmann method can not only track exactly and automatically the interface, but also the simulation results have a good qualitative agreement with ones of the previous experimental and numerical studies.展开更多
We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3Y-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of part...We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3Y-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of particles as a function of Cw in very dilute suspension using light scattering method, and obtained the surface features of the sedi- ment of suspension with different Cw using SEM. We also discussed the influence of the microstructure of adsorbed polymer layers on particles and their interactions in the dis- persing medium on the stability of suspension. Then two different stable states and two different unstable states for 3Y-TZP suspension were given. Accordingly, the (Cw, η), (Cw, α), and (α, η) two-parameter, and (Cw, α, η) three-parameter stability maps were con- structed. Based on the DLVO theory calculations, the dispersant concentration, particle distance (r), and interparticle potential energy (VT) maps with various solids loading for 3Y-TZP aqueous suspension were also constructed. In (Cw, r) two-parameter coordinate system, the stable motion region map for particles was established. The Cw, α, and VT,max (the highest potential energy) surface of the potential barrier map was obtained through calculation and simulation on the basis of the surfaces of Cw, r, VT maps introduced above. The (Cw, α) two-parameter stability map was then obtained from the Cw, α, VT,max map. The results showed that this theoretical map can qualitatively prove the experimentally obtained results—the existence of different dispersed states of particles in suspension system and the variation tendency of suspension stability with changing each parame- ter—were reasonable.展开更多
We derive the mesoscopic interparticle potentials from macroscopic thermodynamics for van der Waals,Redlich-Kwong,and Redlich-Kwong-Soave equations of state and find that all these potentials are very similar to the L...We derive the mesoscopic interparticle potentials from macroscopic thermodynamics for van der Waals,Redlich-Kwong,and Redlich-Kwong-Soave equations of state and find that all these potentials are very similar to the Lennard-Jones potential.To investigate the interfacial property at the mesoscale level,we incorporate free energy functions into the single-component multiphase lattice Boltzmann model and obtain the saturated density coexistence curves and interface mass density profiles across the interface using this method with different equations of state.The simulation results accurately reproduce the properties of equilib-rium thermodynamics.Numerical results for single-component phase transitions indicate that a bubble-growth process is obtained and the equilibrium phase diagram is achieved at a given temperature.Bulk free energy,the interfacial energy coefficient,and other properties of nonequilibrium thermodynamic parameters,which are used to examine interfacial properties,are obtained in these simulations,and all these parameters are found to obey irreversible thermodynamics.展开更多
基金Project supported by the National Natrual Science Foundation of China (Grant No.10872123)
文摘Based on the lattice Boltzmann method（LBM）,an improved pseudo-potential model,combined with a method of adding force term,is used to simulate the two-phase flows caused by a liquid droplet impacting on a liquid film.In this model,the different phases are treated as one fluid,and the interfaces between the vapor and liquid phases can be obtained by density value of the fluid.This variant of the LBM allows one to obtain the densities of vapor and liquid with high accuracy.The model is validated by an example of phase separation.The early stage of the impact of droplet on liquid film is simulated,and the results are qualitatively consistent with physical phenomena.
文摘Sedimentation in dilute suspensions of charged particles with thin double layers was investigated. The study covered sedimentation in polydisperse systems at a large Péclet number. The pair-distribution equation was solved by a regular perturbation method, and it was found that generally speaking the sedimentation coefficient deviates slightly from that at the infinitely large Péclet number except that the double layer was very thin. The results were found to pos- sess much more diversities than the case of hard spheres.
基金supported by the National Natural Science Foundation of China(41977024,41601236)the Fundamental Research Funds for the Central Universities(2452019078).
文摘Soil interparticle forces can pose important effects on soil aggregate stability and rainfall splash erosion.Meanwhile,these interparticle forces are strongly influenced by specific ion effects.In this study,we applied three monovalent cations(Li^(+),Na^(+),and K^(+))with various concentrations to investigate the influence of specific ion effects on aggregate stability and splash erosion via pipette and rainfall simulation methods.The specific ion effects on soil interparticle forces were quantitatively evaluated by introducing cationic non-classical polarization.The results showed that aggregate stability and splash erosion had strong ion specificity.Aggregate breaking strength and splash erosion rate at the same salt concentration followed the sequence as Li^(+)>Na^(+)>K^(+).With decreasing salt concentration,the difference in aggregate breaking strength or splash erosion rate between different cation systems increased initially(1–10^(-2)mol L^(–1))and later was nearly invariable(10^(–2)–10^(–4)mol L^(–1)).The experimental results were well quantitatively explained by soil interparticle forces considering cationic non-classical polarization.Furthermore,both aggregate breaking strength and splash erosion rate of three cations revealed a strong positive linear relation with net force subjected to cationic non-classical polarization(R^(2)=0.81,R^(2)=0.81).These results demonstrated that different non-classical polarization of cations resulted in different soil interparticle forces,and thus led to differences in aggregate stability and splash erosion.Our study provides valuable information to deeply understand the mechanisms of rainfall splash erosion.
基金supported by the Ministry of Education and Science of the Republic of Kazakhstan under grant 1415/GF2(IPC 21)。
文摘In the present work two component dense semiclassical plasma of protons and electrons is considered.Microscopic and electrodynamic properties of the plasma by molecular dynamic simulation are investigated.For these purposes semiclassical interparticle potential which takes into account quantum mechanical diffraction and symmetry effects is used.The considered range of density of plasma is n=1022cm^(−3)to n=1024cm^(−3).Fluctuations and dynamic dielectric functions were calculated using velocity autocorrelation functions.
基金Sponsored by the National Nature Science Foundation of China(Grant No.51276030,51176017)
文摘In this paper, the lattice-Bohzmann method is used to investigate the droplet dynamics after impact on horizontal and inclined solid surface. The two-phase interparticle potential model is employed. The model is found to possess a linear relation between the macroscopic properties （ surface tension σ and contact angle α） and microscopic parameters （ G, G, ）. The flow state of the droplet on the surface is analyzed in detail, and the effects of surface characteristic, impact velocity, impact angle, the viscosity and surface tension of the liquid are investigated, respectively. It is shown that the lattice-Bohzmann method can not only track exactly and automatically the interface, but also the simulation results have a good qualitative agreement with ones of the previous experimental and numerical studies.
文摘We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3Y-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of particles as a function of Cw in very dilute suspension using light scattering method, and obtained the surface features of the sedi- ment of suspension with different Cw using SEM. We also discussed the influence of the microstructure of adsorbed polymer layers on particles and their interactions in the dis- persing medium on the stability of suspension. Then two different stable states and two different unstable states for 3Y-TZP suspension were given. Accordingly, the (Cw, η), (Cw, α), and (α, η) two-parameter, and (Cw, α, η) three-parameter stability maps were con- structed. Based on the DLVO theory calculations, the dispersant concentration, particle distance (r), and interparticle potential energy (VT) maps with various solids loading for 3Y-TZP aqueous suspension were also constructed. In (Cw, r) two-parameter coordinate system, the stable motion region map for particles was established. The Cw, α, and VT,max (the highest potential energy) surface of the potential barrier map was obtained through calculation and simulation on the basis of the surfaces of Cw, r, VT maps introduced above. The (Cw, α) two-parameter stability map was then obtained from the Cw, α, VT,max map. The results showed that this theoretical map can qualitatively prove the experimentally obtained results—the existence of different dispersed states of particles in suspension system and the variation tendency of suspension stability with changing each parame- ter—were reasonable.
基金supported by the, National Natural Science Foundation of China (50406012, 51076172)the National Key Laboratory of Bubble Physics and Natural Circulation of NPIC (9140C710901090C71, 9140C7101020802)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20090191120017)
文摘We derive the mesoscopic interparticle potentials from macroscopic thermodynamics for van der Waals,Redlich-Kwong,and Redlich-Kwong-Soave equations of state and find that all these potentials are very similar to the Lennard-Jones potential.To investigate the interfacial property at the mesoscale level,we incorporate free energy functions into the single-component multiphase lattice Boltzmann model and obtain the saturated density coexistence curves and interface mass density profiles across the interface using this method with different equations of state.The simulation results accurately reproduce the properties of equilib-rium thermodynamics.Numerical results for single-component phase transitions indicate that a bubble-growth process is obtained and the equilibrium phase diagram is achieved at a given temperature.Bulk free energy,the interfacial energy coefficient,and other properties of nonequilibrium thermodynamic parameters,which are used to examine interfacial properties,are obtained in these simulations,and all these parameters are found to obey irreversible thermodynamics.
