Aerosol Transport Phenomena: A Tale of Two Knudsen Numbers

CHRISTOPHER J. HOGAN, University of Minnesota

     Abstract Number: 11
     Working Group: Plenary Lecture Invited by Conference Chair

Abstract
While aerosol research draws on fundamental principles from physics, chemistry, and engineering, there are several unique features in aerosol transport phenomena that make aerosol science a distinct discipline in its own right. This presentation will attempt to overview the development of aerosol science’s uniqueness through an understanding of Knudsen numbers. First, I will provide an overview of the momentum transfer, or 'gas-phase,' Knudsen number, which governs the slip correction factor as well as the drag and diffusion of particles. This will include recent developments in modeling the slip correction factor for non-spherical particles, particles traveling at transonic to supersonic speeds, and nanometer-scale clusters where vapor molecules sorb and desorb during migration. Second, I will discuss the diffusive Knudsen number, which governs rates of condensation, coagulation, and particle charging. This discussion will begin with Fuchs’s limiting sphere theory and explore how it can be coupled with atomistic simulations to precisely characterize aerosol growth, charging, and heat transfer rates. The presentation will conclude with a discussion of outstanding questions in aerosol transport phenomena and potential pathways for introducing aerosol science to a broader audience.