VISUALIZATION AND COLLECTION OF OVERSPRAY FROM AIRLESS SPRAY PAINTING

Short Description
of airless spray painting through flow visualiza-. tion [3], then applies this knowledge to point the. way toward aerodynamically-effective collection …

Website: www.mne.psu.edu | Filesize: 574kb

Content
8 INTERNATIONAL SYMPOSIUM ON FLOW VISUALIZATION (1998)
1-1
VISUALIZATION AND COLLECTION OF OVERSPRAY
FROM AIRLESS SPRAY PAINTING
Gary S. Settles, James D. Miller, Thomas J. Hartranft, and Aaron D. Brandt
Keywords: spray painting, liquid atomization and sprays, non-Newtonian fluids, environmental engineering,
pollution control, two-phase flows
Abstract
Spray painting generates serious airborne pollution
through “overspray”, the fraction (typically
50% or more) of the paint which fails to reach its
target. This paper examines the phenomenology
of “airless” spray painting by flow visualization,
and shows how the knowledge thus gained can be
used to capture the overspray efficiently near its
source. Results show that the airless spray
painting process combines the fluid-dynamic
phenomena of wavy-sheet breakup, spray entrainment,
spray impingement, inertial droplet
impaction, and the turbulent wall jet. In view of
this, the paper considers how the overspraycontaining
wall jet might be induced to separate,
roll up, and be drawn away in a particular direction
where it can be filtered to remove the overspray
particles. The design of an aerodynamically-
correct overspray collector results from
these considerations.
1 Introduction
Millions of gallons of paint are sprayed every
year worldwide. However, of the many…