Investigation into nanoparticle fluidization characteristics with electrostatic force-modified population balance model

Within the two-fluid model framework integrated with particle dynamics theory, this study explicitly incorporates interparticle electrostatic forces to derive formulas for aggregation and breakage kernels of nanoparticle aggregates. Accordingly, an electrostatic-force-modified Population Balance Model (PBM) is proposed to track and characterize nanoparticle aggregation and breakage processes. To quantify the evolution of aggregate volume fractions and diameters, the flow characteristics of SiO₂ nanoparticles in a microfluidized bed are numerically investigated. The results demonstrate that the modified PBM enhances the dispersion of aggregates and improves fluidization quality. The electrostatic force increases with growing aggregate diameter. When nanoparticles enter the fully fluidized stage, the synergistic interplay among electrostatic repulsion, Brownian diffusion, and turbulent forces collectively regulates aggregate formation and breakage. This leads to a more organized spatial distribution of aggregates and a gradual reduction in local pressure drop fluctuations over time. Furthermore, the bed pressure difference increases significantly under the combined influence of gas velocity and electrostatic forces.