Modeling coalescence in multiple-particle systems

Analytical models for particle coalescence are generally limited to considering binary pairs of particles, yet coalescence continues in large multi-particle aerosol aggregates formed at high temperature. A computationally efficient model, incorporating an analytical function to approximate the fluid interface, is presented for the viscous coalescence of linear multiple-particle systems. The dynamics of interfacial evolution are approximated by employing a modification of the boundary integral approach in which a single point is used to solve the equations for the surface velocities. For the early stages of coalescence, the solution showed asymptotic behavior as the number of particles increased, and, from these results, an empirical expression for the asymptotic solution to the time dependence of the coalescence parameter was determined: b=1-0.2934t0.8914b=1-0.2934t0.8914. Estimates of the coalescence dynamics beyond the limitations of the modified boundary integral approach are made by using a semi-empirical model for the decay of the surface area. Model predictions of the shrinkage for a system of three particles compare favorably to those of finite element models.