论文标题
在瞬态过程中，关于管中大气泡气泡的标准
On the criteria of large cavitation bubbles in a tube during a transient process
论文作者
论文摘要
极端的空化场景，例如由大气泡气泡引起的瞬时过程中的水柱分离会导致灾难性破坏。在本文中，我们研究了管中大气泡气泡的开始标准和动力学。提出了一个新的空化号$ ca_2 = {l^*}^{ - 1} ca_0 $，以描述空化气泡的最大长度$ l _ {\ max} $，其中$ l^*$是水柱的非维度长度，表示其细长，$ ca_0 $是经典的固定号。结合加速诱导的空化的发作标准（$ CA_1 <1 $，PAN等人（2017）），我们表明，大型圆柱气泡气泡的发生需要$ CA_2 <1 $和$ CA_1 $和$ CA_1 <1 <1 <1 $ $。我们还建立了一个瑞利型模型，用于在管中大型气泡气泡的动力学。气泡以有限端的速度崩溃，从最大气泡大小到崩溃的时间为$ t_c = \ sqrt {2} \ sqrt {ll _ {\ max}} \ sqrt {\ sqrt {\fracρ长度，$ρ$是液体密度，$ p _ {\ infty} $是远场中的参考压力。使用修改的“管道避难”设备对系统实验进行了分析结果，该设备可以解除加速度和速度。当前工作中的结果可以指导遇到瞬态过程的液压系统的设计和操作。
Extreme cavitation scenarios such as water column separations in hydraulic systems during transient processes caused by large cavitation bubbles can lead to catastrophic destruction. In the present paper, we study the onset criteria and dynamics of large cavitation bubbles in a tube. A new cavitation number $Ca_2 = {l^*}^{-1} Ca_0$ is proposed to describe the maximum length $L_{\max}$ of the cavitation bubble, where $l^*$ is a non-dimensional length of the water column indicating its slenderness, and $Ca_0$ is the classic cavitation number. Combined with the onset criteria for acceleration-induced cavitation ($Ca_1<1$, Pan et al. (2017)), we show that the occurrence of large cylindrical cavitation bubbles requires both $Ca_2<1$ and $Ca_1<1$ simultaneously. We also establish a Rayleigh-type model for the dynamics of large cavitation bubbles in a tube. The bubbles collapse at a finite end speed, and the time from the maximum bubble size to collapse is $T_c=\sqrt{2}\sqrt{lL_{\max}}\sqrt{\fracρ{p_\infty}}$, where $l$ is the length of the water column, $L_{\max}$ is the maximum bubble length, $ρ$ is the liquid density, and $p_{\infty}$ is the reference pressure in the far field. The analytical results are validated against systematic experiments using a modified 'tube-arrest' apparatus, which can decouple acceleration and velocity. The results in the current work can guide design and operation of hydraulic systems encountering transient processes.
