The Study Of Aerosol Particle Dynamics Based On Taylor Series Expansion Moment Method

The dynamic characteristics of aerosol particles in the air,such as coagulation,broken and growth,can be described by general dynamics equations.When solving the nonlinear general dynamical equations,the moment method is a method with low computation costs and high accuracy.The Taylor series expansion moment method(TEMOM),which closes the moment equations by Taylor series expansion approximation,is widely used because of its high computational efficiency.Based on this moment method,the brownian coagulation in the zero-dimensional system in the continuum-slip regime and that in one-dimensional diffusion condition in the continuum-slip regime are studied.Then,the fifth-order TEMOM model and its error estimation in the free molecular regime are given.In this paper,the TEMOM model in the zero-dimensional system in the the continuum-slip regime is given,using an universal Cunningham correction coefficient.The Cunningham correction coefficient is fully expanded and partly expanded,respectively.The relative errors between the results obtained by these two expansion methods and the results obtained before are all small.What's more,the application of the TEMOM model in this paper is extended to the case when Knudsen number is 10.Adding the influence of diffusion in,the TEMOM model in one-dimensional diffusion condition in the continuum-slip regime is given.The effect of diffusion and the effect of brown condensate on the particles are mainly related to the Peclet number and the Damk?hler number.When Pe or Da is large,the effect of diffusion is weakened,and the rate of brownian coagulation is accelerated.Finally,using the Taylor series moment method,the fifth-order TEMOM model of particles in the free molecular regime is given.This fifth-order TEMOM model is compared with the third-order TEMOM model in the free molecular regime,which further validatesthe third-order TEMOM model has high efficiency and accuracy.Then,the error estimation of the fifth order TEMOM model in the free molecular regime is studied.It is found that the total error is mainly related to the first six moments of the particles.