A collision model for a large number of particles with significantly different sizes

A collision model, modified from the Smoluchowski model, is developed for simulating coagulation and growth of a large number of aerosol particles with significantly different sizes. In this collision model, the particle-size distribution is discretized in volume bins, and the total mass among all the bins is conserved. In situations with significantly different particle sizes, the present model reduces the number of bins compared with the previous models, thus reducing the computational cost. By comparing the results of the present model with the exact solution of Smoluchowski’s original model, the accuracy of the solution is not sacrificed. Therefore, this model enables the real-time simulation of three-dimensional, two-phase flow when flow/particle interactions need to be considered. After implementation with a flow solver, the model is further validated with the data from a smoke-reduction experiment in a room-scale chamber using flow-injected nanoparticle aggregates.