SIMULATION OF AGGREGATION DURING THE FLOW OF COLLOIDAL DISPERSIONS

A computer simulation was used to analyze the processes of aggregates deformation and destruction in a shear flow. Central and noncentral. i nteractions between the particles are considered without regard for th e hydrodynamic interactions (the so-called approximation of free penet ration). Multiply connected chains responsible for the mechanical prop erties of the aggregated systems are shown to be formed as a result of the structural rearrangement in a system of particles with exclusivel y central interaction. The fractal dimension of the secondary aggregat es, which are formed after destruction of the primary aggregates in a shear flow, slightly increases with the shear rate, whereas the radius of gyration decreases according to the power law with an exponent of 0.4 - 0.5. The effects of Brownian motion and noncentral interaction a re analyzed qualitatively. The Brownian motion gives rise to the break age of the aggregates into smaller and denser fragments. The presence of a noncentral component of interaction that is affected by the varia tion in the angle between neighboring bonds results in a situation whe re at small loads the aggregates behave as rigid bodies, while at larg er loads the aggregates become more brittle, i.e., they break into sma ller fragments.