title: Dynamic forces on agglomerated particles caused by high-intensity ultrasound.
abstract: In this paper the acoustic forces on particles and agglomerates caused by high-intensity ultrasound in gaseous atmosphere are derived by means of computational fluid dynamics (CFD). Sound induced forces cause an oscillating stress scenario where the primary particles of an agglomerate are alternatingly pressed together and torn apart with the frequency of the applied wave. A comparison of the calculated acoustic forces with respect to the inter particle adhesion forces from Van-der-Waals and liquid bridge interactions reveals that the separation forces may reach the same order of magnitude for 80 μm sized SiO2-particles. Hence, with finite probability acoustically agitated gases may de-agglomerate/disperse solid agglomerate structures. This effect is confirmed by dispersion experiments in an acoustic particle levitation setup.
authors.affiliation: Department of Particles and Process Engineering, University of Bremen, Foundation Institute of Materials Science, Badgasteiner Str. 3, D-28359 Bremen, Germany. Electronic address: knoop@iwt.uni-bremen.de.
authors.forename: Claas
authors.initials: C
authors.lastname: Knoop
authors.affiliation: Department of Particles and Process Engineering, University of Bremen, Foundation Institute of Materials Science, Badgasteiner Str. 3, D-28359 Bremen, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Fritsching
mesh_terms: D003102:Colloids / Q000737:chemistry* / Q000528:radiation effects*; D003198:Computer Simulation; D019220:High-Energy Shock Waves; D008422:Materials Testing; D008956:Models, Chemical; D010316:Particle Size; D011829:Radiation Dosage; D012822:Silicon Dioxide / Q000737:chemistry* / Q000528:radiation effects*; D013010:Sonication / Q000379:methods*; D013314:Stress, Mechanical
chemical_list: D003102:Colloids; D012822:Silicon Dioxide
keywords: Acoustic forces; Finite volume method; High intensity ultrasound; Non-linear acoustics; Standing wave field