Bradley-Hamaker theory

To accoimt for the effect of the particle velocity, the expression for VLIM was multiphed with a parameter of hnear function of particle velocity. For particles of diameter smaller than 20 pm, the particle—surface adhesion energy was calculated using the Bradley—Hamaker theory. ° In this theory, the particle—surface adhesion energy is determined through the concept of London—van der Waals forces (this assumption is only vahd for small particle sizes). For the case of a particle colliding with a cylindrical fibre, the adhesion energy is given by ... 

Usually, additive particles are of maximum size of about 100 qm and the cohesive forces cannot be neglected. The significance of the cohesive forces is in the disintegration of the cluster, which requires that the hydrodynamic forces exceed the cohesive forces. Assuming the aggregates are formed by nontouching spherical particles of like material, the Bradley-Hamaker theory (Elmendorp, 1991) allows one to calculate the attractive van der Waals force between two particles as... 

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