The Use of Quadrature Method of Moments (QMOM) in Studying the Mechanisms of Aerosol Agglomeration and its Practical Use

Abstract

The efficiency of dust collector is relatively low when dealing with PM2.5. Agglomerating the aerosols under acoustic field is a preliminary method to make the efficiency improve. Acoustic agglomeration of aerosol mainly includes four mechanisms: orthokinetic interaction, hydrodynamic interaction, acoustic wake effect and Brown agglomeration. All mechanisms have their own characteristics with the change of acoustic field. Among witch orthokinetic interaction plays the leading role, while Brown agglomeration is the weakest. Besides, Brown agglomeration is only related to the change of temperature and other air characteristics, thus it changes little under the effect of acoustic field. Compared with experimental methods, simulating the agglomerate process on computer is much faster and more economical. To overcome the flaws of traditional ways in simulation of long-time, hard to make exact hypotheses and difficult to make the formulas close, quadrature method of moments (QMOM) is employed when doing simulations, and taking it into practical use. The results of QMOM show a good match with group method, while it takes less time and does not need to make unnecessary hypotheses. Besides studying the characteristics of acoustic agglomeration, QMOM will also be easy to be used in other fields of studies with similar dynamic equations.

Coupling Eulerian‐Lagrangian method of air‐particle two‐phase flow with population balance equations to simulate the evolution of vehicle exhaust plume

“…Different moments have different physical meanings and are helpful for analyzing some properties of the aerosol particles …”

“…Different moments have different physical meanings and are helpful for analyzing some properties of the aerosol particles. 31 By applying the moment operator in Equation (25) to the PBE in Equation (20), a set of moment equations can be derived into a general form as given by Equation (26)…”