AEROSOL DYNAMICS MODELING USING THE METHOD OF MOMENTS

A numerical approach to the solution of an aerosol dynamics system is presented. It is accurate, extremely economical, applicable to any combination of aerosol processes, and it does not require prior knowledge of the particle-size distribution function. The approach is based on the solution of differential equations for the moments of the particle-size distribution function. Two numerical techniques are discussed. The first technique involves approximating the collision-frequency coefficient with a single 'effective' value and the second uses interpolation techniques to evaluate time derivatives of the moments of the distribution function. The methods are tested with a variety of examples in the free-molecular regime against the results computed with a discrete model. As a severe test, an example of simultaneous particle nucleation, coagulation, and surface reaction is considered.