Microbubble expansion in a flexible tube.
Microbubble expansion in a flexible tube.
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DOI：
10.1115/1.2206200
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发表时间：
2006-08
期刊：
影响因子：
--
通讯作者：
T. Ye;J. Bull
中科院分区：
文献类型：
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作者：
T. Ye;J. Bull
我们已经利用了一个计算模型的膨胀的微泡在液体填充的柔性管，以调查的潜力声汽化的全氟化碳液滴损伤血管在一种新的气体栓塞治疗技术的潜在治疗肿瘤。该模型采用固定网格、多区域、界面跟踪、直接数值模拟的方法，将所有界面和边界视为尖锐的不连续面，以获得高精度。在目前的工作中，我们研究了初始气泡尺寸对液滴蒸发产生的流动和壁面应力的影响。其余的无量纲参数，支配系统的响应（雷诺数，韦伯，和Strouhal数，初始气泡压力，和壁的刚度和张力）被选择来模拟小动脉。柔性管的结果与刚性管的结果显著不同。由于气泡和管变形的联合作用，出现两种主要的流动状态：在管端的流入和在气泡表面附近的流出。管的柔性在很大程度上消散了刚性管模型中产生的极端压力。在柔性管中，快速变化的压力的大小和总膨胀时间都大大减少。相对于血管直径，较小的初始气泡直径导致较低的壁应力。这项研究表明，壁的灵活性可以显着影响血管内的全氟化碳液滴的声学汽化所产生的壁应力，并表明，在较大的，更灵活的血管液滴的声学激活可能是不太可能损坏或破裂的血管比激活更小，更硬的血管。
We have utilized a computational model of the expansion of a microbubble in a liquid-filled flexible tube to investigate the potential for acoustic vaporization of perfluorocarbon droplets to damage blood vessels during a novel gas embolotherapy technique for the potential treatment of tumors. This model uses a fixed grid, multi-domain, interface tracking, direct numerical simulation method that treats all interfaces and boundaries as sharp discontinuities for high accuracy. In the current work, we examined effects of initial bubble size on the flows and wall stresses that result from droplet vaporization. The remaining dimensionless parameters that govern the system response (Reynolds, Weber, and Strouhal numbers, initial bubble pressure, and wall stiffness and tension) were selected to model an arteriole. The results for a flexible tube are significantly different from those for a rigid tube. Two major flow regimes occur due to the combined effect of bubble and tube deformation: in flow at the tube ends and out flow near the bubble surface. The flexibility of the tube largely dissipates the extreme pressure that develops in the rigid tube model. Both the magnitude and the overall expansion time of the rapidly changing pressure are greatly reduced in the flexible tube. Smaller initial bubble diameters, relative to the vessel diameter, result in lower wall stresses. This study indicates that wall flexibility can significantly influence the wall stresses that result from acoustic vaporization of intravascular perfluorocarbon droplets, and suggests that acoustic activation of droplets in larger, more flexible vessels may be less likely to damage or rupture vessels than activation in smaller and stiffer vessels.