Computation of local enhancement factors for the quantification of particle deposition patterns in airway bifurcations
Computation of local enhancement factors for the quantification of particle deposition patterns in airway bifurcations
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DOI：
10.1016/s0021-8502(98)00040-8
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发表时间：
1999-02-01
影响因子：
4.5
通讯作者：
Heistracher, T
中科院分区：
文献类型：
--
作者：
Balashazy, I;Hofmann, W;Heistracher, T
通过数值求解三维Navier-Stokes方程和蒙特卡罗方法模拟颗粒在撞击、沉积、扩散和截留共同作用下的运动轨迹，计算了两种不同几何模型下的支气管分叉的空间沉积模式。为了量化预测沉积图案的不均匀性，用预先指定的表面积元素扫描了分叉口的整个表面，以确定每单位表面积沉积的颗粒数量。将给定表面元素的局部沉积密度相对于平均沉积密度定义为局部沉积增强因子，在本研究中，局部沉积增强因子的计算集中在吸气颗粒沉积模式上。结果表明，对于所考虑的所有颗粒尺寸和分叉几何形状，沿分叉表面的局部沉积增强因子的分布具有很强的不均匀性。对于直径在0.01~10微米范围内的任何颗粒，用100微米×100微米的扫描元件获得的分叉处的最大增强因子在上支气管气道中约为100。这些数值计算的局部沉积增强因子可以直接应用于吸入健康影响方案，以考虑高度局部剂量的影响。(C)1998爱思唯尔科学有限公司。保留所有权利。
Spatial deposition patterns in two different geometric models of bronchial airway bifurcations were computed by solving numerically the 3D Navier-Stokes equations and simulating particle trajectories under the simultaneous action of impaction, sedimentation, diffusion, and interception by Monte Carlo techniques. To quantify the inhomogeneities of the predicted deposition patterns the whole surface of the bifurcation was scanned with a prespecified surface area element to determine the number of particles deposited per unit surface area. The local deposition density in a given surface element, relative to the average deposition density, was then defined as the local deposition enhancement factor.In the present study, the computation of local deposition enhancement factors focused on inspiratory particle deposition patterns. Our results revealed that the distributions of local deposition enhancement Factors along the surface of a bifurcation exhibit strong inhomogeneities for all particle sizes and bifurcation geometries considered here. The maximum enhancement factor in a bifurcation was found to be about 100 in the upper bronchial airways for any particle size in the diameter range from 0.01 to 10 mu m, obtained with a 100 mu m x 100 mu m scanning element. These numerically computed local deposition enhancement factors can be directly applied to inhalation health effect protocols to consider the effects of highly localized doses. (C) 1998 Elsevier Science Ltd. All rights reserved.