The breakup characteristics of micro rectangular jets with external disturbances were experimentally investigated. The hydraulic diameter of the orifice changed from 0.1 mm to 0.4 mm, whereas the aspect ratio of the cross section varied from 10 to 30. The external disturbance was generated by the piezoelectric ceramic, which was excited by a function generator with a frequency from 0 kHz to 15 kHz. The results showed that the evolution of the ejected rectangular jet experienced three stages from the nozzle to the downstream locations, namely, the axis-switching rectangular jet, the disturbance induced jet fluctuation, and the structured droplet train after the breakup. The time period of the axis-switching wave was independent of jet Weber number. The axis-switching jet could breakup into orderly droplet train, equally spaced droplet stream with same droplet size, when the jet velocity and disturbance frequency felled in a specific region for a given nozzle. In order to generate a droplet train with desired droplet size and frequency in some applications, the nozzle size and jet velocity should be carefully selected. Moreover, it was found that the area-based equivalence diameter was better than the hydraulic diameter as the characteristic length for rectangular jets.

实验研究了具有外部扰动的矩形微射流的破裂特性。孔的水力直径从0.1 mm变为0.4 mm，而横截面的长宽比从10变为30。压电陶瓷产​​生外部干扰，压电陶瓷由函数发生器激发，频率为0 kHz至15 kHz。结果表明，从喷嘴到下游位置，喷射的矩形射流的演化经历了三个阶段，即轴切换矩形射流，扰动引起的射流起伏和破碎后的结构化液滴流。轴转换波的时间周期与射流韦伯数无关。轴切换射流可能分裂成有序的液滴流，当喷射速度和扰动频率在给定喷嘴的特定区域内下降时，具有相同液滴尺寸的等距液滴流将下降。为了在某​​些应用中生成具有所需液滴大小和频率的液滴列，应谨慎选择喷嘴大小和喷射速度。此外，发现基于面积的当量直径比水力直径更好，这是矩形射流的特征长度。