Liquid plug propagation in flexible microchannels: A small airway model.
Liquid plug propagation in flexible microchannels: A small airway model.
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DOI：
10.1063/1.3183777
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发表时间：
2009-07
影响因子：
4.6
通讯作者：
Y. Zheng;H. Fujioka;S. Bian;Y. Torisawa;D. Huh;S. Takayama;J. Grotberg
中科院分区：
文献类型：
--
作者：
Y. Zheng;H. Fujioka;S. Bian;Y. Torisawa;D. Huh;S. Takayama;J. Grotberg
在本研究中，我们调查的影响，壁的灵活性上的塞子传播和由此产生的壁应力在小气道模型的实验测量和数值模拟。在实验上，一个灵活的微通道制造模仿灵活的小气道使用软光刻。产生液体塞并通过微通道传播。局部壁面变形是瞬时发生的，最大变形量随塞速的增大而增大。测量并观察到塞两端的压降随塞速度的增加而增加，并且与刚性通道中的压降相比，柔性通道中的压降略小。然后，提出了一个计算模型来模拟稳定的插头传播通过一个灵活的通道对应的实验装置中的中间平面。结果表明，定性协议与实验的壁面形状和压力损失和差异带来了有趣的问题，目前的建模领域。弹性壁在塞芯附近向内变形，随着塞速的增加，塞芯变形和压降增大。壁变形和产生的应力随不同的纵向张力而变化，即，对于大的壁面纵向张力，壁面轻微变形，这使得柔性壁面上的流体应力和应力梯度比刚性壁面上的流体应力和应力梯度减小;然而，发现在具有小的纵向张力的高度变形的壁面上，壁面应力梯度大得多。因此，在诸如肺气肿的疾病中，由于更大的壁应力和应力梯度，具有更大的可变形气道，所以很有可能诱导沿着气道的衬里细胞上的损伤。
In the present study, we investigate the effect of wall flexibility on the plug propagation and the resulting wall stresses in small airway models with experimental measurements and numerical simulations. Experimentally, a flexible microchannel was fabricated to mimic the flexible small airways using soft lithography. Liquid plugs were generated and propagated through the microchannels. The local wall deformation is observed instantaneously during plug propagation with the maximum increasing with plug speed. The pressure drop across the plug is measured and observed to increase with plug speed, and is slightly smaller in a flexible channel compared to that in a rigid channel. A computational model is then presented to model the steady plug propagation through a flexible channel corresponding to the middle plane in the experimental device. The results show qualitative agreements with experiments on wall shapes and pressure drops and the discrepancies bring up interesting questions on current field of modeling. The flexible wall deforms inward near the plug core region, the deformation and pressure drop across the plug increase with the plug speed. The wall deformation and resulting stresses vary with different longitudinal tensions, i.e., for large wall longitudinal tension, the wall deforms slightly, which causes decreased fluid stress and stress gradients on the flexible wall comparing to that on rigid walls; however, the wall stress gradients are found to be much larger on highly deformable walls with small longitudinal tensions. Therefore, in diseases such as emphysema, with more deformable airways, there is a high possibility of induced injuries on lining cells along the airways because of larger wall stresses and stress gradients.