Observations of the collapses and rebounds of millimeter-sized lithotripsy bubbles
Observations of the collapses and rebounds of millimeter-sized lithotripsy bubbles
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DOI：
10.1121/1.3626157
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发表时间：
2011-11-01
影响因子：
2.4
通讯作者：
Sapozhnikov, Oleg A.
中科院分区：
文献类型：
--
作者：
Kreider, Wayne;Crum, Lawrence A.;Sapozhnikov, Oleg A.
由碎石机冲击波激发的气泡经历了长时间的增长，随后是惯性坍缩和反弹。除了与临床碎石治疗相关外，这些气泡还可用于研究惯性塌陷的力学。特别是，已知气泡内蒸汽和不可冷凝气体分子之间的相变和扩散会改变单个气泡的崩溃动力学。因此，在水温为20 ~ 60℃，溶解气体浓度为饱和度的10% ~ 85%的条件下，通过实验观察碎石机气泡的崩塌和反弹，探讨了热和质量输运在惯性崩塌过程中的作用。气泡响应通过高速摄影和声学测量来确定单个气泡崩溃的时间。通过估算气泡崩塌前后的最大直径，并利用相应的体积比估算气泡崩塌后保留的能量比例。这些反弹在统计上与溶解气体浓度和温度都有显著的相关性。在许多观测中，表明不对称气泡崩塌的液体射流是可见的。气泡反弹对这些不对称非常敏感，主要是在耗散性崩塌最多的水条件下。(C) 2011美国声学学会。(DOI: 10.1121/1.3626157)
Bubbles excited by lithotripter shock waves undergo a prolonged growth followed by an inertial collapse and rebounds. In addition to the relevance for clinical lithotripsy treatments, such bubbles can be used to study the mechanics of inertial collapses. In particular, both phase change and diffusion among vapor and noncondensable gas molecules inside the bubble are known to alter the collapse dynamics of individual bubbles. Accordingly, the role of heat and mass transport during inertial collapses is explored by experimentally observing the collapses and rebounds of lithotripsy bubbles for water temperatures ranging from 20 to 60 degrees C and dissolved gas concentrations from 10 to 85% of saturation. Bubble responses were characterized through high-speed photography and acoustic measurements that identified the timing of individual bubble collapses. Maximum bubble diameters before and after collapse were estimated and the corresponding ratio of volumes was used to estimate the fraction of energy retained by the bubble through collapse. The rebounds demonstrated statistically significant dependencies on both dissolved gas concentration and temperature. In many observations, liquid jets indicating asymmetric bubble collapses were visible. Bubble rebounds were sensitive to these asymmetries primarily for water conditions corresponding to the most dissipative collapses. (C) 2011 Acoustical Society of America. [DOI: 10.1121/1.3626157]