Experimental Study on Breakup and Transition of a Rotating Liquid Jet

The present study pertains to the experimental work on the characteristic of a rotating liquid jet under various conditions of the nozzle diameter, volumetric flow rate and rotating speed. With emphasis on the important phenomena of a liquid jet, the effects of breakup length, the transition between dripping and jetting, breakup categories, droplet sizes from the breakup, and the time interval between two successive droplets are investigated systematically. The results reveal that the breakup length of a jet increases with flow rate and decreases with imposed rotation. The hysteresis behavior only occurs for larger nozzles, and the transition from jetting to dripping is affected by the imposed rotation. Depending on the imposed rotation, three different breakup patterns are found and named single droplet, satellite droplet, and multi-position necking. An empirical correlation is also proposed to predict the boundary of satellite and multi-droplets formation. The main droplet, satellite droplet, and merged droplet are about 1.8, 0.8, and 2.2 times than the nozzle diameters, respectively, no matter what the rotating speed is. Moreover, the non-dimensional time interval between two main droplets has an ascending tendency with either We number or the imposed rotation.