Review of Aerosol Forces Under Nonstandard Conditions: Modeling and Applications

REN GARITY, James Henry, Andrew Metcalf, John Saylor, Sarah Suffield, Clemson University

     Abstract Number: 365
     Working Group: Aerosol Physics

Abstract
When discussing forces on aerosol particles under standard conditions, gravity and inertia are often emphasized as the “major” forces affecting settling and deposition. However, under nonstandard conditions, such as environments with steep temperature gradients, high humidity, or turbulent flow, other forces can attain the same order of magnitude as gravity and inertia. These “minor” forces, such as diffusiophoresis, thermophoresis, Stefan flow, and Saffman lift, can significantly affect particles under nonstandard conditions, especially on particle sizes of less than one micron.

In this talk, we will introduce a review of forces in addition to gravity and inertia that can have significant effects on particles with diameters less than one micron under nonstandard conditions. Along with our review of the forces, we have also developed a MATLAB code and app, which we have named the Aerosol Calculator Application for Theoretical Modeling (AeroCATm). AeroCATm has advantages over other box modeling and chemistry applications as it has the capacity to calculate psychrometric properties of air, and therefore accounts for nonstandard conditions. The purpose of AeroCATm is to compare the magnitudes of various forces affecting deposition under short-range transport conditions, with the goal of helping users determine what environmental factors will be most relevant for their situation.

In this talk, we will also discuss applications of our findings. In terms of its applications, AeroCATm has the flexibility and capability to handle a variety of environments. Its primary reason for development is quantifying sea salt aerosol deposition in spent nuclear fuel dry cask storage containers, which involves a hot, potentially high-humidity environment under a transition flow regime. These conditions can also be present in industrial processes such as dust collectors and dryers, and examples of these situations will be provided to showcase AeroCATm’s performance.