Numerical Study of Sheet Cavitation Breakoff Phenomenon on a Cascade Hydrofoil
Numerical Study of Sheet Cavitation Breakoff Phenomenon on a Cascade Hydrofoil
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DOI：
10.1115/1.1596239
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发表时间：
2003-07
影响因子：
2
通讯作者：
Y. Iga;M. Nohmi;A. Goto;B. Shin;T. Ikohagi
中科院分区：
文献类型：
--
作者：
Y. Iga;M. Nohmi;A. Goto;B. Shin;T. Ikohagi
本文对叶栅中最基本的单元--翼型的二维非定常空泡流进行了数值计算。重点研究了薄板空腔在瞬态空泡条件下的失稳现象，并对破裂现象的机理进行了探讨。采用可压缩气液两相介质的局部均匀模型，采用TVD MacCormack格式对上述空腔流动进行了数值模拟。本方法可以处理整个空化/非空化非定常流场。通过对数值结果的详细分析，可以看出，薄板空腔的破裂现象至少存在两种机制：一种是重入射流在这种破裂现象中起主导作用，另一种是空腔内传播的压力波导致了另一种伴随空腔表面波的破裂现象。
2-D unsteady cavity flows through hydrofoils in cascade which is the most fundamental element of turbomachinery are numerically calculated. In particular, attention was paid to instability phenomena of the sheet cavity in transient cavitation condition and the mechanism of break-off phenomenon was examined. A TVD MacCormack's scheme employing a locally homogeneous model of compressible gas-liquid two-phase media was applied to analyze above cavity flows. The present method permits us to treat the whole cavitating/noncavitating unsteady flow field. By analyzing numerical results in detail, it became clear that there are at least two mechanisms in the break-off phenomena of sheet cavity; one is that re-entrant jets play a dominant role in such a break-off phenomenon, and the other is that pressure waves propagating inside the cavity bring about an another type of break-off phenomenon accompanied with cavity surface waves.