流动聚焦装置中微气泡的形成与夹断标度指数
Microbubble formation and pinch-off scaling exponent in flow-focusing devices
摘要：
我们研究了气体射流破碎和由此产生的微气泡形成的微流体流动聚焦装置，使用超高速成像在1百万帧/秒。在最近的实验中[Dollet等人，物理修订信函100，034504（2008）]发现，在坍缩的最后阶段，颈部的半径与时间成比例，具有1/3幂律指数，这表明气体惯性和伯努利抽吸效应变得重要。在这里，超高速成像用于捕获完整的气泡轮廓并量化通过颈部的气体流量。它揭示了由于伯努利吸力而导致的压力下降太低，无法解释加速夹断。高时间分辨率的图像使我们能够接近夹断的最终时刻在1 μs内。我们观察到，气泡夹断的最后时刻的特征在于标度指数为0.41 +/- 0.01。该指数约为2/5，其可以基于以下观察结果导出：在塌陷期间，由于通过液体惯性的排他性驱动，颈部变得不那么细长。
英文摘要：
We investigate the gas jet breakup and the resulting microbubble formation in a microfluidic flow-focusing device using ultra high-speed imaging at 1 million frames/s. In recent experiments [Dollet et al., Phys. Rev. Lett. 100, 034504 (2008)] it was found that in the final stage of the collapse the radius of the neck scales with time with a 1/3 power-law exponent, which suggested that gas inertia and the Bernoulli suction effect become important. Here, ultra high-speed imaging was used to capture the complete bubble contour and quantify the gas flow through the neck. It revealed that the resulting decrease in pressure, due to Bernoulli suction, is too low to account for an accelerated pinch-off. The high temporal resolution images enable us to approach the final moment of pinch-off to within 1 μs. We observe that the final moment of bubble pinch-off is characterized by a scaling exponent of 0.41 +/- 0.01. This exponent is approximately 2/5, which can be derived, based on the observation that during the collapse the neck becomes less slender, due to the exclusive driving through liquid inertia.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
