Experimental study of liquid jets injected in crossflow

摘要

In this paper, we studied the behavior of liquid sheet and jet injection into a low-speed crossflow. Characteristics of primary breakup in a liquid sheet and jet are investigated for circular and rectangular orifices. Effect of dimensionless numbers on primary breakup regimes including jet trajectory, length, height, breakup, and spray characteristics are surveyed by the shadowgraphy technique at ambient pressure and temperature. Tests were performed in the range of 0.8-16.57 for the Weber number, 5-250 for the momentum flux ratio, and 380-1850 for the Reynolds number. This comprehensive study on rectangular jets in crossflow leads to introduce the transition regions of the primary atomization regime. Our observation demonstrated that the most substantial effects relating to the axis-switching in rectangular orifices. The axis-switching determines the region of mode transition, the height and the lenght of the jet, and the structure of bags formation. Besides, the inherent differences in axis-switching behavior are the substantial difference in the various configurations of rectangular orifices. In the orthogonal configuration, no axis-switching for moderately high Weber number causes to be more bent of column jet and consequently delay on bag regime threshold, regardless of our expectations. A similiar explanation could be applied for other observations in the primary atomization of rectangular nozzles.