BREAKUP OF LIQUID JETS EMANATING FROM ELLIPTICAL ORIFICES AT LOW FLOW CONDITIONS

This article presents experimental results on the breakup behavior of liquid jets emanating from elliptical orifices with different orifice aspect ratios. The experiments were carried out in the range of mean jet velocity 0−5 m/s, using water as the working fluid; the liquid jets were injected vertically downward in still, ambient air. Photographic methods were employed to analyze the breakup characteristics of the liquid jets. The breakup curves of the elliptical orifice jets are compared with those of circular orifices with the same exit area as the elliptical orifices. The comparison shows that the liquid jets emanating from the elliptical orifice are less stable than jets from the circular orifice in a particular range of flow conditions corresponding to a √We range of 2−20. We attribute this enhanced instability of the elliptical jet to the axis-switching process occurring in this √We regime, a phenomenon by which the elliptical jet interchanges major and minor axes periodically as the jet flows downstream. The breakup process of the elliptical jet resembles that of the circular jet below this range of flow conditions, and their breakup curves coincide. Above this range, the elliptical liquid jets exhibit different flow behavior from the circular jet, although their breakup curves coincide again.