纳米流体的制备和分散稳定性是纳米流体研究工作的前提。本文利用平衡分子动力学模拟方法,尝试从微观角度研究纳米流体的分散稳定性。以纳米颗粒Cu在液态CO_2中的分散稳定为算例,通过跟踪每个固体分子和液体分子的位置,分别观察了颗粒周围的液体吸附现象和颗粒的团聚现象。通过改变固液分子间的引力和斥力,观察其对颗粒周围液体分子的密度分布和颗粒团聚的影响。模拟结果显示,颗粒周围存在液体吸附层;增加固液间的引力,可以提高颗粒周围吸附液体分子的数目,但不改变液体层厚度;固液间引力的增强还可以有效抑制或延迟团聚的发生。这为纳米颗粒的分散稳定提供了新的思路。 The preparation and dispersion stability of nanofluids are the prerequisites of nanofluid research. In this paper, equilibrium molecular dynamics simulation method is used to study the dispersion stability of nanofluids from the microscopic point of view. Taking the dispersion stability of nanoparticle Cu in liquid CO_2 as an example, the phenomenon of liquid adsorption and the agglomeration of particles were observed by tracking the position of each solid molecule and liquid molecule. By changing the gravitational and repulsive forces between solid and liquid molecules, the influence of the density of liquid molecules around the particles and the agglomeration of particles is observed. The simulation results show that there is a liquid adsorption layer around the particles. Increasing the gravitation between the solid and the liquid can increase the number of molecules adsorbed around the particles, but does not change the thickness of the liquid layer. Increasing the gravitation between solid and liquid can also effectively restrain or delay the occurrence of agglomeration . This provides a new way for the dispersion stability of nano-particles.