抄録
Injecting liquid downward into the stationary atmosphere from an oblong-orifice of 0.15mm x 1.3mm, the breakup behavior of the liquid jet was observed in detail by flash photography. Test liquids employed were water, ethanol and aqua-solutions of propylene-glycol. Liquid injection velocity was ranging from 1 to 20 m/s. It was found that the liquid jet deformed into chains of bamboo-leaf-like liquid films, the edges of the liquid film became thick rims due to the surface contraction, the threaded-beads-like wave of short wave-length appeared on the rims, and the liquid jet broke up regularly due to the wave. The resulting droplets were more uniform and smaller than those of liquid jet from circular-orifice. Satellite droplets were also formed, but the generating frequency was not so high. The characteristics of interfacial wave on liquid jet and the size distribution of droplets were investigated by image analysis. Based on the results, the mechanism of regular breakup of the liquid jet from oblong-orifice was discussed. The effects of liquid properties upon the suitable velocity range for regular breakup were also examined. It was supported that the regular breakup of liquid jet should be of use as a simple methodology for uniform-sized droplet production.
