This paper describes the characteristics of twin-fluid atomizers with
and without flow impingement. Malvern RT-Sizer and Particle Image
Velocimetry (PIV) are used to measure particle size and spray flow field,
respectively. Velocity measurement by PIV system indicates that the spray
flow is decelerated in the axial direction and accelerated in the radial
direction, resulting in a highly interactive flow pattern between particles. It
also results in the formation of a large scale vortex and enhances the flow
entrainment near the substrate. Results also show that the particle
distribution of the atomizer with external substrate is more concentrated,
indicating the re-distribution of the spray droplets during the flow
impingement. The particle size can be lowered down to 4.51μm under a low
injection pressure of 2 bars. It also implies that the flow impingement can
be used as the mechanism to control the particle size distribution of the
spray flow for various engineering applications.