Measuring the dynamic parameters of liquid fragments generated in the near-field
of atomizing sprays poses a significant challenge due to the random nature of
the fragments, the instability of the spray, and the limitations of current
measuring technology. Precise determination of these parameters can aid in
improving the control of the atomization process, which is necessary for
providing suitable spray structures with appropriate flow rates and droplet size
distributions for various applications such as those used in heat engines. In
piston and gas turbine engines, controlling spray characteristics such as
penetration, cone angle, particle size, and droplet size distribution is crucial
to improve combustion efficiency and decrease exhaust emissions. This can be
accomplished by adjusting the structural and/or operating parameters of the fuel
supply system. This article aims to measure the breakup length, spray cone
angle, axial velocity, breakup time, and liquid sheet film thickness for a swirl
air-blast atomizer used in a gas-steam engine. The measurement was conducted
using a shadowgraph imaging system developed specifically for this study,
consisting of a high-speed camera, a lens, and a light source. While lasers are
commonly used as light sources in the literature, this study utilized a special
LED high-speed pulse light generator, which is cheaper, easier to handle, and
provides a more uniform background. Images were processed using a MATLAB code
developed for this study. Although the breakup zone is naturally random and the
breakup location significantly varies with time, the novel method developed in
this study helps quantify critical parameters under different operating
conditions.
