Electrostatically-Assisted Removal of Charged Bumpy and Rough Particles in Turbulent Airflows

The detachment of charged, bumpy, and rough particles from rough surfaces in turbulent airflow in an electric field was studied. Electrostatic forces between the charged particles and the conductive surface were evaluated for various electric fields. Particles with corona ion charges, Boltzmann charge distribution, and saturation charges were considered. The enhanced JKR model was used to determine the adhesion force between micro-particle bumps and surfaces with fine roughness. Attention was given to particle rolling detachment in turbulent airflows when electrostatic forces contribute to the removal process. That is, the electrostatic Coulomb + force points away from the surface, and hydrodynamic drag force and moment led to the rolling detachment of particles from the surface. The corresponding critical shear velocities for particle resuspension from a substrate were evaluated and compared against the experimental data. The effects of particle size, irregularity, and surface roughness for particle removal were studied. It was shown that appropriate electric fields could significantly reduce the shear velocity needed for particle removal. In fact, a sufficiently high electric field intensity could electrostatically remove the particle in the absence of airflow. Finally, the theoretical findings showed that the electrostatic effects could significantly improve the particle removal and surface cleaning processes.