帯電エアロゾル流による沈着・再飛散同時現象 沈着層に及ぼす粒子の電荷と外部電界の影響

Abstract

Formation of particle deposition layer was investigated as a simultaneous phenomenon of particle deposition and reentrainment in a turbulent aerosol flow. Aerosol particles passed through a corona charger were pneumatically transported into a glass tube equipped with a ring-type electrode, and the deposition layers formed on the tube wall in various conditions were quantitatively analyzed with particular attention to the effects of particle charge and external electric field on the deposition layer. The charged particles formed a deposition layer of a filmy pattern around the electrode being independent of the polarity of particle charge and applied voltage. The mass of deposition layer increased with elapsed time and became constant after an equilibrium state of particle deposition and reentrainment. The time dependency was represented by an exponential equation; the time constant decreased with increasing particle charge and/or applied voltage, and the equilibrium mass of deposition layer increased with the particle charge. Furthermore, it was found that appropriate arrangement of electrodes to control external electric field eliminates the filmy pattern deposition layer.