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使用改进的多松弛时间格子玻尔兹曼方法(MRT-LBM)对近壁空泡溃灭演化过程开展了数值模拟, 并对空泡溃灭诱发壁面损伤的作用力机制进行研究. 首先, 对改进外力格式的多松弛伪势模型开展Laplace定律验证和热力学一致性验证; 然后, 结合改进外力格式的多松弛伪势模型对近壁空泡溃灭演化进行数值模拟, 获得了近壁空泡溃灭过程的流场细节, 着重研究了溃灭过程中空泡的动力学行为. 研究发现, 近壁空泡溃灭过程中释放的微射流主要来源于第1次溃灭, 而冲击波的产生来源于第1次溃灭和第2次溃灭, 且第2次溃灭产生的冲击波强度显著高于第1次溃灭产生的冲击波; 进一步, 对近壁空泡溃灭过程中壁面处压力与速度的分布特性进行分析, 研究空泡溃灭作用于壁面的载荷机制. 研究发现, 壁面受到冲击波和微射流的共同作用, 冲击波作用范围大, 造成面损伤, 而微射流作用在局部区域, 造成点状破坏. 研究结果揭示近壁空泡溃灭演化过程以及空泡溃灭诱发壁面损伤的作用力机制, 为进一步利用空化效应及减少空蚀带来的破坏提供理论支撑.
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关键词:
- 多松弛时间格子玻尔兹曼方法 /
- 伪势模型 /
- 近壁空泡溃灭 /
- 空蚀
To reveal the load mechanism of wall damage induced by bubble collapse, the near-wall cavitation bubble collapse evolution is numerically simulated using an improved multi-relaxation-time lattice Boltzmann method (MRT-LBM), and the dynamic behavior of near-wall cavitation bubble is systematically analyzed. First, the improved multi-relaxation pseudopotential model with a modified force scheme is introduced and validated through the Laplace law and thermodynamic consistency. Subsequently, the near-wall bubble collapse evolution is simulated using the improved model, and the process of the bubble collapse evolution is obtained. The accuracy of the numerical simulation results is confirmed by comparing with previous experimental results. Based on the obtained flow field information, including velocity and pressure distributions, the dynamic behaviors during the bubble collapse are thoroughly analyzed. The results show that the micro-jets released during the near-wall bubble collapse primarily originate from the first collapse, while the shock waves are generated during both the first and the second collapse. Notably, the intensity of the shock waves produced during the second collapse is significantly higher than that during the first collapse. Furthermore, the distribution characteristics of pressure and velocity on the wall during the near-wall bubble collapse are analyzed, revealing the load mechanism of wall damage caused by bubble collapse. The results show that the wall is subjected to the combined effects of shock waves and micro-jets: shock waves cause large-area surface damage due to their extensive propagation range, whereas micro-jets lead to concentrated point damage with their localized high-velocity impact. In summary, this study elucidates the evolution of near-wall bubble collapse and the load mechanism of wall damage induced by bubble collapse, which provides theoretical support for further utilizing the cavitation effects and mitigation of cavitation-induced damage.-
Keywords:
- multi-relaxation-time lattice Boltzmann method /
- pseudopotential model /
- collapse of near-wall bubble /
- cavitation erosion
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