Comparison of discrete, discrete-sectional, modal and moment models for aerosol dynamics simulations

Abstract

An open source software (Aerosol and Air Quality Research Lab-Aerosol Dynamics Model, AAQRL-ADM) used for aerosol dynamics simulations is developed by including four models: discrete, discrete-sectional, method of moments, and modal. First, the mathematical description of these models as well as the effects of aerosol dynamics available in the software are reviewed, and a modal model is developed to use multiple modes to represent particle size spectrum. Second, the design of a working principle and user graphical interface (GUI) of AAQRL-ADM is described. Third, the models in AAQRL-ADM are validated by investigating the evolution of particle size distribution (PSD) in considering the effects of coagulation, condensation, and nucleation. Next, the trade-off between simulation accuracy and numerical efficiency is discussed for all of the four models, and a guide to choosing the appropriate aerosol dynamic model in practical simulation is presented. Finally, discrete-sectional, moment, and modal models are used to investigate the particle size distribution in a furnace aerosol reactor along a streamline, coupled with the velocity and temperature profiles. AAQRL-ADM is provided free of charge for the use of public researchers.

Aerosol Dynamics Model for Estimating the Risk from Short-Range Airborne Transmission and Inhalation of Expiratory Droplets of SARS-CoV-2

“…In this approach, a modal form of size distribution was assumed wherein the total volume range for the aerosol droplets is divided into discrete modes. 42 Thus, from eq 2 , the evolution of number concentration of each mode with time and spatial position can be described by …”

“…The modal numerical scheme was used in this study to solve the droplet transport equation (eq ) as it is easily applicable for multicomponent systems and can account for the solute’s effect on evaporation. In this approach, a modal form of size distribution was assumed wherein the total volume range for the aerosol droplets is divided into discrete modes . Thus, from eq , the evolution of number concentration of each mode with time and spatial position can be described by …”

Mini Review on Gas-Phase Synthesis for Energy Nanomaterials

“…However, the GDE for multicomponent aerosols not only includes the aforementioned mechanisms, but also considers the variation of chemical composition with particle size. The GDE for an aerosol distribution is given as , The first term on the left-hand side (LHS) is the rate of change of the PSD in the particle volume interval, ν to ν + d ν . The second term on the LHS considers the aerosol convection and diffusion in the background fluid, the third term on the LHS accounts for particle condensation or evaporation at rate G , and the last term on the LHS describes the formation of new particles of critical volume ν* at rate I .…”

“…Wu and Flagan (1998) presented a discrete-sectional model to simulate the aerosol evolution associated with fast chemical reactions as well as coagulation and evaporation/condensation. Discrete-sectional model represents the size distribution of molecular clusters by each cluster size and still uses sections to describe particles whose sizes are much larger than the molecular cluster (usually larger than 10 nm) . Biswas et al (1997) employed the discrete-sectional model to predict the evolution of the nanocomposite aerosol size distribution in a multicomponent iron–silicon system in a flame reactor.…”

Description of nucleation, growth and coagulation processes in the modeling of debris formation after a nuclear burst

“…The temporal variations in the conditions of the systems also produce an approximate continuum of particle sizes. For computational purposes functional representations of the number and mass distributions need to be used and several approaches have been developed as part of the studies of other particle-forming systems (Zhang et al [2020]). They can be classified as those that assume the general functional form of the size distributions and those that create a partitioning of the particle-size domain and only impose a functional dependence within each of those sections (bins).…”