Effect of gravity on liquid plug transport through an airway bifurcation model.
Effect of gravity on liquid plug transport through an airway bifurcation model.
复制标题
重力对气道分叉模型中液体塞输送的影响。
DOI：
10.1115/1.1992529
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Grotberg,JB
中科院分区：
文献类型：
--
作者：
Zheng,Y;Anderson,JC;Suresh,V;Grotberg,JB
许多医学治疗需要将液体塞滴注到肺气道中并在整个肺气道中递送。改善这些治疗需要更好地了解液体如何分布在这些气道中。在这项研究中，重力和表面机制确定滴注液体的分布进行了实验研究，使用一个台式模型的对称分叉气道。将液体塞滴入母管中，并通过注射泵驱动通过分叉。通过改变分叉的横滚角和俯仰角来调节重力的影响确定了两个子管的相对重力方向：当一个子管较低时，（在重力作用下有利的）确定了重力沿母管的轴向方向沿着作用的分量：时，重力的非零分量沿母管的轴向方向沿着作用。分流比被定义为刚在塞分流之后上部子体中的液体体积与下部子体中的液体体积的比率。我们测量了分流比，作为一个函数：母管毛细管数;的债券数（Bo）;和预先存在的塞子最初阻塞任一子管的存在。发现存在一个临界毛细管数，在此临界值以下，液体不能进入上子体，在此临界值以上，在一定条件下，堵塞和未堵塞的情况下，随着Bo的增加，毛细管数增加，并趋于平稳，而随着Bo的增加，毛细管数减少。与非堵塞情况相比，在一定时间内减少（增加），而在上（下）液阻情况下增加（减少）。当一个子管堵塞时，更多的液体进入未堵塞的子管，并且重力效应越大，这种效应越大。一个简单的理论模型，预测和定性协议的实验在很大范围内的参数。
Many medical therapies require liquid plugs to be instilled into and delivered throughout the pulmonary airways. Improving these treatments requires a better understanding of how liquid distributes throughout these airways. In this study, gravitational and surface mechanisms determining the distribution of instilled liquids are examined experimentally using a bench-top model of a symmetrically bifurcating airway. A liquid plug was instilled into the parent tube and driven through the bifurcation by a syringe pump. The effect of gravity was adjusted by changing the roll angleand pitch angleof the bifurcation (was isogravitational).determines the relative gravitational orientation of the two daughter tubes: when, one daughter tube was lower (gravitationally favored) compared to the other.determines the component of gravity acting along the axial direction of the parent tube: when, a nonzero component of gravity acts along the axial direction of the parent tube. A splitting ratio, is defined as the ratio of the liquid volume in the upper daughter to the lower just after plug splitting. We measured the splitting ratio,, as a function of: the parent-tube capillary number; the Bond number (Bo);;; and the presence of pre-existing plugs initially blocking either daughter tube. A critical capillary numberwas found to exist below which no liquid entered the upper daughter, and above whichincreased and leveled off with.increased whiledecreased with increasing,, and Bo for blocked and unblocked cases at a given. Compared to the nonblockage cases,decreased (increased) at a givenwhileincreased (decreased) with an upper (lower) liquid blockage. More liquid entered the unblocked daughter with a blockage in one daughter tube, and this effect was larger with larger gravity effect. A simple theoretical model that predictsandis in qualitative agreement with the experiments over a wide range of parameters.