Cavitation flow instability of subcooled liquid nitrogen in converging–diverging nozzles
Cavitation flow instability of subcooled liquid nitrogen in converging–diverging nozzles
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DOI：
10.1016/j.cryogenics.2011.11.001
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发表时间：
2012
期刊：
影响因子：
2.1
通讯作者：
K. Ohira;T. Nakayama;T. Nagai
中科院分区：
文献类型：
--
作者：
K. Ohira;T. Nakayama;T. Nagai
对喉部直径分别为1.5和2.0mm的两种缩扩式圆喷管内过冷液氮的空化流动不稳定性进行了实验研究。同时进行了流动观察，以澄清两种喷嘴之间的不稳定现象和空化行为的差异。随着过冷液氮温度的降低，空化模式由连续模式转变为间歇模式。当液体的温度达到约76 K时，在两个CD喷嘴中发生这种变化。伴随大流量振荡的间歇模式的发生被认为是由在单组分汽液流中声速的急剧减小引起的，因为声速在空化期间限制了CD喷嘴中的喉部速度。间歇模式下的振荡压力值远大于连续模式下的振荡压力值，在74和76 K之间达到峰值。间歇模式下的振荡压力的大小可以由空化发生之前的喉部静压与空化发生期间的喉部静压之间的差来评估。
The cavitation flow instability of subcooled liquid nitrogen in two types of converging-diverging (CD) circular nozzles with throat diameters of 1.5 and 2.0 mm was experimentally investigated. Flow observations were also performed to clarify the instability phenomenon and the differences in cavitation behavior between the two nozzles. The cavitation mode changed from continuous mode to intermittent mode as the temperature of the subcooled liquid nitrogen decreased. This change occurred in both CD nozzles when the temperature of the liquid reached approximately 76 K. Occurrence of the intermittent mode accompanying large-flow oscillations was considered to be caused by a drastic reduction of the speed of sound in the single-component, vapor-liquid flow because the speed of sound restricted the throat velocity in the CD nozzle during cavitation. Oscillation pressure values in intermittent mode were much larger than those in continuous mode, peaking between 74 and 76 K. The magnitude of the oscillation pressure in intermittent mode could be evaluated from the difference between the throat static-pressure immediately prior to the occurrence of cavitation and that during cavitation.