Estimation on the strength of a liquid bridge adhered to three spheres

The minimum structure of a stable agglomerate in a fluidized beds is composed of not two particles, but more than three particles. The strength of a liquid bridge adhered to three spheres, which has been scarcely evaluated except for a pair of spheres, was estimated both by numerical simulation for a static bridge and by experimental data for a dynamic bridge within the volume range of a pendular bridge. A bridge force must be defined not at the normal neck bridge in a pair of spheres, but only at the contact line with a sphere. Numerical results estimated the maximum dimensionless static force that acted on spheres at the considerably smaller value, 1.1, than the experimental identical dynamic force. Dynamic force profiles were approximated by a power estimator with -1.2 exponent, and depend on bridge volume and Ohnesorge number composed of a stretching speed and liquid viscosity. The dimensionless displacement of a moving sphere up to 0.04 described the characteristic range of increased static and dynamic bridge forces. (C) Koninklijke Brill NV, Leiden and Society of Powder Technology, Japan, 2008.