THESIS
2016
xv, 117 pages : illustrations (some color) ; 30 cm
Abstract
The detachment of an aerosol from a solid surface is an important phenomenon. The
detachment of a particle is a process during which a solid particle or liquid droplet on a surface
leaves its’ original position. They can slide or roll on the surface or even be re-suspended to
become airborne again. Detachment of aerosols from solid surfaces is a concern in many
different industrial and environmental processes. It is undesirable in many scenarios, e.g.
contamination in the manufacturing of microelectronics and semiconductors, spraying of
pesticide and paint, resuspension of filtered particles, and disease transmission. Sometimes it is
also desirable, e.g., surface decontamination, filtration, oil recovery. Understanding the
detachment behaviour can help in improving the numerous...[
Read more ]
The detachment of an aerosol from a solid surface is an important phenomenon. The
detachment of a particle is a process during which a solid particle or liquid droplet on a surface
leaves its’ original position. They can slide or roll on the surface or even be re-suspended to
become airborne again. Detachment of aerosols from solid surfaces is a concern in many
different industrial and environmental processes. It is undesirable in many scenarios, e.g.
contamination in the manufacturing of microelectronics and semiconductors, spraying of
pesticide and paint, resuspension of filtered particles, and disease transmission. Sometimes it is
also desirable, e.g., surface decontamination, filtration, oil recovery. Understanding the
detachment behaviour can help in improving the numerous engineering operations and
protecting human health. One droplet type and two substrate materials were studied. The
resuspension behaviours for solid aerosols and liquid aerosols are not necessarily the same.
Unlike solid particles, liquid may deform under an applied force and a portion of the droplet
may detach even if the removal force is not high enough to detach the whole droplet. Three
experiments were conducted to investigate the detachment of a droplet from a substrate, they
were a centrifuge experiment, wind tunnel experiment and air jet impingement experiment. In
the centrifuge experiment, a constant removal force field was provided by a centrifuge and the
detachment behaviour was investigated. Larger droplets split into smaller portions during
detachment; some portions were detached and the remains formed smaller droplets on the
substrate. The wind tunnel experimental investigated the deformation and detachment of liquid
droplets on two different solid surfaces in a fully developed turbulent channel flow. The air jet
impingement experiment studied the detachment of droplets on a plastic substrate. Droplets of
two different size ranges were impinged by an air jet with different impinging angles.
Post a Comment