Molecular dynamics simulation of effect of temperature on Cu nanoparticles agglomeration of nanofluids

The agglomeration of nanoparticles is a key factor which affects the stability of nanofluids. In order to analyze the effect of temperature on the agglomeration of nanoparticles from a micro perspective, molecular dynamics method is adopted to investigate the agglomeration characteristics of Cu nanoparticles in liquid water. Two conditions of stationary state and flow state are considered in the simulation. The results show that the collision and agglomeration accelerate with the increase of fluid temperature for either stationary state or flow state. The aggregation of particles can be divided into the Brown movement stage, the adhesion stage, and the coalescence stage. The centroid distances of nanoparticles no longer change when the aggregation process completes. The potential energy of the system increases with the fluid temperature. The total potential energy of the system decreases with each collision of Cu particles. The total potential energy of the system no longer changes until all the Cu particles collide and agglomerate. The obtained results can provide useful understanding of the stability of nanofluids affected by the temperature. And the stability further affects the thermal behavior of nanofluids.