The reopening of a collapsed fluid-filled elastic tube
The reopening of a collapsed fluid-filled elastic tube
复制标题
重新打开塌陷的充满液体的弹性管
作者：
A. Juel;A. Heap
本文对坍塌的充液弹性管的重开机理进行了实验研究。该实验是一个简单的机械模型，旨在评估现有理论模型的稳健性。内径Ri=4.88±0.14 mm的长一米长的水平弹性管内填充了硅油，并小心地机械折叠。在初始瞬变衰减之后，以恒定的流量注入氮气会导致空气指状物的稳定传播。这一行为是在毛细管数Ca的可实现范围内观察到的，毛细管数Ca测量粘性力和毛细管力的比率。随着钙含量的增加，管子坍塌段和重开段之间的过渡区变短，气泡尖端后面的管子高度增大。我们还发现，空气手指可以在部分重新开放的管道中传播，在这些管道中，跨壁压力在指尖后面很远的地方是负的。通过对运动粘度分别为1000cS、200cS和100cS的三种不同牌号的硅油进行实验，探讨了粘度对重开动力学的影响。在实验压力对钙的依赖关系和零重力三维呼吸道再开放模型的数值模拟之间的直接比较。ASME：J.Biomech。英文，第128卷，2006年，第473页)突出了一些显著的区别。在实验参数范围内，重力对重启力学有多方面的深刻影响。重开管由刚性底座支撑，这导致了围绕折叠管水平中面的不对称性，导致了随着钙的增加，重开的不同阶段。此外，浮力作用在空气指上，空气指在管子横截面的顶部附近传播，在下面留下了更厚的流体衬里。在小钙范围内，再开管高度随粘度的增加而显著增加。实验证据表明，由于浮力的增加，这种粘度的增加导致了传播手指后面的膜结构发生了显著的变化。改变的膜结构改变了管壁上的机械载荷，从而改变了重新打开的管的形状。
We present an experimental study of the reopening mechanics of a collapsed liquid-filled elastic tube. The experiment is a simple mechanical model of pulmonary airway reopening and aims to assess the robustness of existing theoretical models. A metre-long horizontal elastic tube of inner radius Ri=4.88 ± 0.14mm is filled with silicone oil and is carefully collapsed mechanically. The injection of nitrogen at a constant flow rate results in the steady propagation of an air finger, after the decay of initial transients. This behaviour is observed over the realizable range of the capillary numbers Ca, which measures the ratio of viscous and capillary forces. With increasing Ca, the transition region between the collapsed and reopened sections of the tube shortens, and the height of the tube behind the bubble tip increases. We also find that air fingers can propagate in partially reopened tubes, in which the transmural pressure is negative far behind the finger tip. The effect of viscosity on the reopening dynamics was explored by performing experiments using three different grades of silicone oil, with kinematic viscosities of 1000cS, 200cS and 100cS. A direct comparison between the experimental pressure dependence on Ca and numerical simulations of the zero-gravity three-dimensional airway-reopening model of Hazel & Heil (Trans. ASME: J. Biomech. Engng, vol. 128, 2006, p. 473) highlights some significant differences. Within the experimental parameter range, gravity profoundly influences the reopening mechanics in several ways. The reopening tube is supported by a rigid base, which induces an asymmetry about the horizontal mid-plane of the collapsed tube, resulting in distinct phases of reopening as Ca increases. In addition, buoyancy forces act on the air finger, which is observed to propagate near the top of the cross-section of the tube, leaving a thicker fluid-lining below. In the limit of small Ca, the height of the reopened tube increases significantly with viscosity. Experimental evidence suggests that this increase in viscosity leads to significant changes in the film configuration behind the propagating finger, caused by the increased contribution of buoyancy forces. The altered film configuration changes the mechanical load on the tube walls and, hence, the shape of the reopened tube.
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影响因子：
3.3
作者：
GAVER, DP;SAMSEL, RW;SOLWAY, J
通讯作者：
SOLWAY, J
离体大鼠肺部气道重新开放压力。
DOI：
10.1152/jappl.1994.76.3.1372
发表时间：
1994
期刊：
Journal of applied physiology (Bethesda, Md. : 1985)
影响因子：
--
作者：
Naureckas,ET;Dawson,CA;Gerber,BS;Gaver3rd,DP;Gerber,HL;Linehan,JH;Solway,J;Samsel,RW
通讯作者：
Samsel,RW
气道关闭是由液膜不稳定引起的吗？
DOI：
10.1016/0034-5687(89)90059-5
发表时间：
1989
期刊：
Respiration physiology
影响因子：
--
作者：
Kamm,RD;Schroter,RC
通讯作者：
Schroter,RC
影响因子：
3.3
作者：
Halpern, D;Jensen, OE;Grotberg, JB
通讯作者：
Grotberg, JB