A consideration of promotion of dissolved gas separation by dynamic stimulation of unsteady cavitating flow
A consideration of promotion of dissolved gas separation by dynamic stimulation of unsteady cavitating flow
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非定常空化流动态刺激促进溶解气体分离的思考
DOI：
10.1299/transjsme.19-00217
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
H. Sasaki
中科院分区：
文献类型：
--
作者：
Y. Iga;Daiki Makii;H. Sasaki
以往的空化基准模拟表明，在大攻角瞬态空化条件下，由于空化具有高度的非定常性，在破裂区，水翼升力被低估。作者认为，传统的汽蚀数值计算方法没有考虑溶解不凝气体的释放，并假定了饱和蒸汽压下的汽蚀发生阈值是造成计算结果偏低的原因之一。本文的空化风洞实验表明，在空化体积基本相同的情况下，非定常空化流中溶解氧的释放量大于准定常空化流中溶解氧的释放量。实验结果对这一假设进行了论证，并指出非定常空化流动的动态激励导致了不凝气的释放。在空化的数值模拟中，分别采用湍流能量、雷诺应力、产生项和斜压力矩来模拟空化的动力刺激。将这些模型应用于汽相空化的均质数值计算方法中，根据局部流场的不同，改变空化出现的阈值。数值结果表明，考虑非定常空化流中不凝气释放的斜压力矩动态模拟，部分改善了升力的低估。
It was shown in the past bench-mark simulation of cavitation that a lift of hydrofoil is underestimated in the break-down region in the condition of transient cavitation at high angle of attack in which cavitation has highly unsteady behavior. The authors assume that one of the reasons of the underestimation is lack of consideration of liberation of dissolved non-condensable gas and assuming the threshold of cavitation appearance at saturated vapor pressure in all the conventional numerical method of cavitation. In the present experiment of cavitation tunnel, it was shown that the liberation amount of dissolved oxygen is larger in unsteady cavitating flow than in quasi-steady cavitating flow although the cavity volumes are almost same. The experimental result gives a reason on the assumption and indicates that the dynamic stimulation with unsteady cavitating flow causes the liberation of non-condensable gas. In the numerical simulation of cavitation, the dynamic stimulation was modeled by turbulent energy, Reynolds stress, production term and baroclinic torque, respectively. The liberation models were applied for homogeneous numerical method of vaporous cavitation, then the threshold value of appearance of cavitation changes according to the local flow field. In the numerical result, it was shown that the underestimation of lift was partially improved by considering liberation of non-condensable gas by the dynamic stimulation of baroclinic torque in the unsteady cavitating flow.
叶栅空化浪涌脉动现象的发生机制及振荡特性
DOI：
--
发表时间：
2009
期刊：
Journal of Environment and Engineering
影响因子：
--
作者：
Yuka IGA;Kei HASHIZUME;Yoshiki YOSHIDA;Toshiaki IKOHAGI
通讯作者：
Toshiaki IKOHAGI
影响因子：
2
作者：
Y. Iga;M. Nohmi;A. Goto;B. Shin;T. Ikohagi
通讯作者：
Y. Iga;M. Nohmi;A. Goto;B. Shin;T. Ikohagi
DOI：
--
发表时间：
2010
期刊：
影响因子：
--
作者：
Yuka IGA;Yoshiki YOSHIDA
通讯作者：
Yoshiki YOSHIDA