Gasdynamic agglomeration of aerosols. I. Acoustic waves

In this paper acoustic agglomeration of aerosols is studied in its simplest form, using a time-averaged form of the coalescence equations. An acoustic coagulation kernel is introduced that neglects all nonlinear effects, as well as particle interactions. Based on this model, it is shown that an acoustic frequency exists that optimizes the coalescence process. This optimum frequency does not have a unique value for all distributions, but for size distributions that are not too wide, it is given by ωopt=1/τ*, where τ* is the relaxation time of a particle having a diameter corresponding to the mode count diameter of the initial size distribution function. The paper also includes the result of a numerical integration of the coalescence equations for typical aerosol distributions, which show their evolution under the influence of a sound wave.