Numerical Analysis of Bubble Collapse with Nonequilibrium Phase Transition by the Ghost Fluid Method
Numerical Analysis of Bubble Collapse with Nonequilibrium Phase Transition by the Ghost Fluid Method
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DOI：
10.1299/kikaib.78.1302
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Y. Jinbo;H. Takahira
中科院分区：
文献类型：
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作者：
Y. Jinbo;H. Takahira
对幽灵流体方法进行了改进，以考虑可压缩液体中气泡破裂时汽液界面的非平衡相变。在本方法中，定义了鬼流体，以满足汽液界面的守恒定律，考虑了非球形气泡破裂时的非平衡凝结和蒸发。同时，在幽灵流体方法中引入了自适应分区网格的思想，以消除剧烈坍塌气泡界面的精细结构。将本方法应用于球形汽泡的破裂，并将数值计算结果与Akhatov等人的实验结果进行了比较。结果表明，即使采用欧拉网格，本方法也能很好地预测球形气泡的剧烈破裂。并用该方法模拟了轴对称非球形汽泡在入射激波与气泡相互作用下的破裂过程。考虑了水蒸气的非平衡凝结和蒸发，成功地模拟了非球形气泡破裂时液体射流的形成和激波的产生。当液体射流在气泡上游表面发展时，由于凝结潜热，靠近上游表面的水蒸气温度升高。气泡反弹后，气泡内部出现了由蒸发引起的低温区。
The ghost fluid method is improved so as to consider the nonequilibrium phase transition at the vapor-liquid interface during the collapse of bubbles in a compressible liquid. In the present method, the ghost fluids are defined so that the conservation laws at the vapor-liquid interfaces are satisfied; the nonequilibrium condensation and evaporation for the collapse of nonspherical bubbles are taken into account. Also, the idea of adaptive zonal grids is implemented in the ghost fluid method to dissolve the fine structure of the interface of the violent collapsing bubble. The present method is applied to the collapse of a spherical vapor bubble, and the numerical results are compared with the experimental results by Akhatov et al. It is shown that the present method can predict successfully the violent collapse of a spherical bubble even though the Eulerian grid is employed. Also, the present method is applied to simulate the collapse of an axi-symmetric nonspherical vapor bubble induced by the interaction of an incident shock wave with the bubble. The liquid-jet formation and the generation of shock waves from the collapsing nonspherical bubble are also simulated successfully by taking the nonequilibrium condensation and evaporation of vapor into account. When the liquid jet develops on the upstream surface of the bubble, the vapor temperature close to the upstream surface increases due to the latent heat by condensation. After the bubble rebounds, the low temperature region caused by the evaporation is found inside the bubble.