An improved categorization of vapor bubble collapse: Explaining the coupled nature of hydrodynamic and thermal mechanisms
An improved categorization of vapor bubble collapse: Explaining the coupled nature of hydrodynamic and thermal mechanisms
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DOI：
10.1016/j.ijheatmasstransfer.2019.118754
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发表时间：
2019-12
影响因子：
5.2
通讯作者：
Raunak Bardia;M. Trujillo
中科院分区：
文献类型：
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作者：
Raunak Bardia;M. Trujillo
这项工作提出了一个数值和理论分析的中间气泡崩溃，在对比的热诱导或惯性主导的崩溃，液体-蒸汽界面的传热和周围液体的平流的影响起着重要的作用。这种类型的塌陷的一个关键区别特征是，界面温度和气泡压力在整个塌陷过程中不断变化。这种行为是由不可忽略的界面蒸汽速度值引起的，其特征在于与气泡表面回归速率相同的量级。这种行为与惯性或热塌缩相反，在惯性或热塌缩中，蒸汽速度基本上为零。在简化了背景系统压力变化率的基础上，给出了一个由B sat和Beff定义参数空间的汽泡溃灭状态图，并扩展了Florschuetz和Chao（1965）以前仅使用B eff的分类。具体而言，目前的工作定量地表明，崩溃行为的变化时，该过程是由一个渐进的加压速率在周围的液相，而不是经常使用的近似阶跃变化。
This work presents a numerical and theoretical analysis of the intermediate bubble collapse, where in contrast to the thermally-induced or inertia dominated collapse, both the effects of liquid-vapor interfacial heat transfer and the advection of the surrounding liquid play an important role. A key distinguishing characteristic of this type of collapse is that the interfacial temperature and bubble pressure are continuously changing throughout the collapse process. This behavior is caused by a non-negligible value for the interfacial vapor velocity, which is characterized by a magnitude of the same order as the bubble surface regression rate. This behavior is in contrast to the inertial or thermal collapse, where, in these regimes, the vapor velocity is essentially zero. Incorporating the rate of change of background system pressure, a regime map for bubble collapse is also presented where the parameter space is defined by B sat and ξ and extends the previous categorization of Florschuetz and Chao (1965) where only B eff was used. Specifically, the present work quantitatively shows that the collapse behavior changes when the process is initiated by a gradual rate of pressurization in the surrounding liquid phase instead of the often used approximation of a step change.