Development and application of moment method on nanoparticles evolution due to coagulation and deposition

Abstract

In this study, the Taylor-series expansion method of moments is developed to describe the dynamic behaviour of nanoparticles considering both the effects of coagulation and deposition in closed environments, where the two effects have always been studied separately before. Compared with traditional methods of moments, the new method could give more accurate results for solving the general dynamics equation. In addition, moment equations with respect to coagulation and deposition considering the fractal dimension (Df) of particles are acquired, and the results are compared with experimental data and are more accurate than the simulation results under the assumption of spherical mode. The new dynamic model could be applied in more real conditions with different microstructures of nanoparticles. With decreasing Df, the particle number concentration decreases more rapidly, additionally, Df has a relatively greater effect on the agglomeration of smaller particles under the same initial concentration. Moreover, the effect of the initial number concentration on coagulation is also studied. The results show that a higher initial number concentration or a smaller particle size could have a greater effect of coagulation on the evolution of particles.