Quantitative analysis of agglomerates levitated from particle layers in a strong electric field

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Vol. 30; no. 10; pp. 2052 - 2058
• Main Authors: Shoyama, Mizuki, Nishida, Shuhei, Matsusaka, Shuji
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2019
• Subjects: Agglomeration; Electrification; External electric field; Levitation; Particle layer; Electrification; Levitation; Particle layer; Agglomeration; External electric field
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2019.06.018

[Display omitted] •Electrification, agglomeration, and levitation of particles are studied.•Primary particles and agglomerates levitated from particle layers are observed.•Effects of particle diameter, electrical resistance, and electric field are analyzed.•Electric field distributions are calculated by considering experimental conditions.•Force balance is used to evaluate critical conditions for the levitation. The electrification, agglomeration, and levitation of particles in a strong electric field were analyzed experimentally and theoretically. Particle layers of glass, alumina, and ferrite were formed on a plate electrode and an external voltage was applied. Microscopic observations of the agglomerates levitated from the particle layers revealed that the number of primary particles constituting an agglomerate is affected by particle diameter and electrical resistance, but not by the applied electric field. The electric field distributions in the system were calculated by considering the charges and geometries of the agglomerates formed on the particle layers. The charges of the agglomerates were obtained experimentally. All forces acting on the agglomerates (i.e., gravitational forces, Coulomb forces, interaction forces between polarized particles, image forces, and gradient forces) were analyzed under different conditions, including various electric field distributions and charges of agglomerates. Furthermore, the critical conditions for the levitation of the agglomerates were evaluated using a force balance.