本文实验研究了蒸馏水经内径0.226 mm、长度16.5 mm薄壁不锈钢直管向真空环境排放时形成的液体闪蒸射流现象.实验观察到3种射流形态。在液体初始温度低于背压所对应的饱和温度时,液体不会发生闪蒸,液体射流喷出后保持完整;反之,液体表面蒸发会导致液体射流核周围出现不规则蒸发波,射流破碎散落;进一步降低背压,会使得射流一出喷口即快速破碎形成扩张角大于90°的雾状射流。射流流量在背压低于某个临界数值时出现壅塞现象,即流量不再随背压降低而增加,表现出强烈的可压缩流动特征。 This paper experimentally studied the phenomenon of liquid flash jet formed when the distilled water was discharged to the vacuum environment through the 0.226 mm inner diameter and 16.5 mm length stainless steel straight tube.The three jet patterns were observed experimentally. When the liquid initial temperature is lower than the saturation temperature corresponding to the back pressure, the liquid does not flash, and the liquid jet remains intact after it is jetted out. On the other hand, evaporation of the liquid surface causes irregular evaporation waves around the liquid jet nucleus, ; To further reduce the back pressure, will make a jet jet that quickly broken to form the expansion angle greater than 90 ° of the mist jet. The jet flow appears clogged when the backpressure is below a certain critical value, ie the flow no longer increases with decreasing backpressure and shows a strong compressible flow characteristic.