Affiliations: State Key Lab. of Fire Science, University of Science
and Technology of China, Hefei, 230026, P. R. China. E-mail:
[email protected] | Tianjin Fire Research Institute, the Ministry of
Public Security, Tianjin, 300381, P. R. China
Abstract: Effervescent atomization is one of the twin-fluid atomization
methods while it has better performance in terms of smaller drop sizes and/or
lower injection pressures. In order to investigate the effects of the internal
flow patterns on droplet characteristics, a new kind of effervescent atomizer
was designed and manufactured. The bubble forming process was visualized with a
high-speed camera, while the droplet size was characterized with a LDV/PDA
system. The experimental results show that there are three regimes of the
two-phase flows inside the discharge orifice, one is bubbly flow, another is
annular flow while the other is the intermittent flow. The flow patterns
transfered from bubbly flow to intermittent flow and then to annular flow with
decreasing of the water flow rate. In addition, with increasing of the working
pressure or decreasing of the water flow rate, the SMD (Sauter mean diameter)
of the droplets decreased and the axial mean velocity increased.
Keywords: Visualization, Water mist, Effervescent atomization, Two phase flow