A molecular dynamics approach for a parametric study of colloidal suspension aggregation kinetics

Interatomic forces significantly influence the flow behavior and dispersion stability of the suspensions in new thermal applications. Using a molecular dynamics technique, the current work focuses on the interatomic forces are estimated. The present analysis accounts for significant contributing factors such as drag force, Brownian force, thermophoresis force, and DLVO potential force of attraction or repulsion by using several nanoparticle dispersions, including SiO2, CNT, and GO in distilled water as the base fluid. Among all the particles considered for the study, Carbon Nanotube (CNT) showed the highest time of stability in the base fluid. That means CNT will take more time to settle down than GO (graphene oxide) and SiO2 due to its lowest density. The drag forces are high for GO (graphene oxide) mixed fluid due to its inherent properties. Another important finding is, below 0.05% volume fraction, the drag forces are insignificant for all the considered samples of analysis. The Brownian force is analyzed for various time intervals, which reports that for the initial periods of collision (Delta t = 0.01) the molecular agitation is greater. However, increasing the Delta t suppresses these forces. From the results, it is clear that the magnitude of Brownian force is dominant with CNT nanofluid, whereas it is the least intensity for SiO2 nano fluid. The magnitude of thermophoresis forces is less than that of drag forces, and it is observed to reach its maximum intensity at T/x = 100, indicating that temperature gradient has a dominant influence on nanoparticle movements. DLVO force of nano particle mixed water is also estimated with respect to volume fraction. Increasing the volume fraction increases the intensity of these forces. These forces are maximum for GO nano fluid.