NUCLEATION AND STABILIZATION OF MICRO-BUBBLES IN LIQUIDS
NUCLEATION AND STABILIZATION OF MICRO-BUBBLES IN LIQUIDS
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DOI：
10.1007/bf00385941
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
CRUM, LA
中科院分区：
文献类型：
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作者：
CRUM, LA
空化和沸腾过程的一个重要方面是核的概念，它充当这些事件开始的优先场所。人们普遍认为，除了极少数情况或特殊控制的实验外，所有空化和沸腾点都起源于这样的核的位置。因此，为了研究这些重要现象，必须尽可能多地了解空化和沸腾中的成核现象。人们普遍认为，自由气泡通常不充当成核位点，因为它们本质上对表面张力导致的溶解不稳定。因此，成核的研究必然与稳定液体内微泡或气泡的机制相关。本文回顾了已提出的各种稳定模型以及支持特定模型的实验证据。对一种特殊的模型——缝隙模型——进行了一些详细的研究，它的预测被用来解释沸腾和空化起始的几种不同的测量。最后，对最近获得的一些关于高强度超声波的破坏性方面的证据进行了检查。该证据的许多方面都表明存在空化现象作为损坏机制。本文还初步解释了由于微泡或空化核通过整流扩散生长而产生的这些效应。
An important aspect of the processes of cavitation and boiling is the concept of a nucleus that acts as a preferential site for the inception of these events. It is commonly thought that except for rare instances or specially controlled experiments, all cavitation and boiling sites originate at the location of such a nucleus. In order to study these important phenomena, then, it is imperative that as much as possible be known about nucleation in cavitation and boiling. It is generally accepted that free air bubbles normally do not act as nucleation sites because they are inherently unstable to dissolution due to surface tension. Thus, the study of nucleation is necessarily associated with mechanisms for stabilizing microbubbles or pockets of gas within the liquid. In this paper, various stabilization models that have been proposed are reviewed as well as the experimental evidence that supports the specific models. One particular model, the crevice model, is examined in some detail, and its predictions are used to explain several different measurements of boiling and cavitation inception. Finally, some evidence that has recently become available concerning the damaging aspects of high intensity ultrasound is examined. Many aspects of this evidence point to the existence of cavitation as the damage mechanism. Also given in this paper are preliminary explanations of these effects due to the growth of microbubbles or cavitation nuclei by rectified diffusion.