Kinetic calculation of transport processes in rarefied gas suspensions with hollow nanoparticles

Abstract

The diffusion of hollow nanoparticles in rarefied gases and the viscosity of rarefied gas nanosuspensions with such particles have been studied using the previously developed kinetic theory. Interaction of the molecules of the carrier gas is described with the Lennard-Jones potential. The interaction of the carrier gas molecules with the nanoparticle is described with RK potential. And interaction of the nanoparticles is described with RKI potential. Gas nanosuspensions based on nitrogen with hollow and solid nanoparticles of aluminum and uranium at temperature of 300 K and atmospheric pressure are considered. The diameter of the nanoparticles ranged from 2 to 100 nm. The hollow nanoparticles had a wall thickness of 1 nm. It is shown that the diffusion coefficients of hollow nanoparticles always exceed that of solid nanoparticles of the same size and of the same material. But this difference does not exceed 1%. It is explained by the smaller depth of well of interaction potential of hollow nanoparticle with carrier gas molecule in comparison with the corresponding value for solid nanoparticles. It is shown that the viscosity of gas nanosuspension with hollow nanoparticles is always lower than that with solid ones. With a certain choice of the material of nanoparticles in a certain range of their sizes, the addition of hollow and solid nanoparticles can cause the opposite effects. Namely, the addition of hollow nanoparticles can reduce the viscosity of the gas nanosuspension compared to that of the pure carrier gas; the addition of solid ones of the same size and of the same material can increase viscosity. The decrease in the viscosity of gas nanosuspensions with hollow nanoparticles can be explained by a smaller mass of hollow nanoparticles compared to solid ones on the basis of the kinetic theory.