Validating CFD predictions of highly localized aerosol deposition in airway models: In vitro data and effects of surface properties
Validating CFD predictions of highly localized aerosol deposition in airway models: In vitro data and effects of surface properties
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DOI：
10.1016/j.jaerosci.2013.01.008
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发表时间：
2013-05-01
影响因子：
4.5
通讯作者：
Longest, P. Worth
中科院分区：
文献类型：
--
作者：
Holbrook, Landon T.;Longest, P. Worth
药物和环境气溶胶的局部沉积控制呼吸道内的解吸、吸收和生物反应。很少有研究报告数值微剂量测定的估计，将这些结果与实验进行比较的研究就更少了。本研究评估了表面涂层和粗糙度对体外非对称双分叉几何结构中吸入粗微米颗粒局部沉积的影响。双分叉几何结构代表了第3-5代气道，并包括来自先前解剖学研究的平均不对称近似值。聚苯乙烯胶乳10 μ m单分散颗粒在60 l/min（LPM）的稳态气管流速下输送，并使用荧光显微镜在0.75 mm见方的网格上分辨平均局部沉积模式。测试的三个气道几何形状表面未改变，涂有硅油，并进行砂磨涂层。对于所采用的硬塑料体外模型，为了防止颗粒反弹和再次夹带，表面涂层显示出重要性。打磨模型以不受控制的方式改变了局部沉积轮廓，因此不建议用于未来的实验。体外结果和CFD模拟之间的最佳总体匹配是涂层实验几何形状和粗糙壁粗糙度模拟。对于这种情况，总沉积的实验和模拟之间的相对误差为6%。在局部沉积的基础上，在x和y方向上的沉积分数的累积线显示实验和模拟之间的合理的协议。然而，在第二分叉处的涂覆实验中观察到沉积后颗粒滚动或扩散的一些证据。比较实验和计算流体动力学的结果细胞的细胞，更高的最大沉积增强因子（DEF）观察到的体外情况下，可能是由于不包括在计算流体动力学模拟的因素。这一结果意味着，先前根据CFD模拟预测的最大DEF值可能较低，体外模型或体内模型的实际值甚至可能高于预测值。总之，本研究提供了一个有价值的新的数据集，了解表面特性对局部沉积的影响，评估气管支气管气道中的热点幅度，并验证CFD预测。(C)2013爱思唯尔有限公司保留所有权利。
Local deposition of pharmaceutical and environmental aerosols governs desorption, uptake, and biological response within the respiratory airways. Few studies have reported estimates of numerical microdosimetry and even fewer have compared these results with experiments. This study evaluated the effects of surface coating and roughness on the local deposition of inhaled coarse micrometer particles in an in vitro asymmetric double bifurcation geometry. The double bifurcation geometry is representative of airway generations 3-5 and includes mean asymmetry approximations from previous anatomical studies. Polystyrene latex 10 mu m monodisperse particles were delivered at a steady state tracheal flow rate of 60 l/min (LPM) and mean local deposition patterns were resolved on a grid of 0.75 mm squares using fluorescent microscopy. The three airway geometry surfaces tested were unaltered, coated with silicone oil, and sanded-coated. For the hard plastic in vitro models employed, coating the surface was shown to be important in order to prevent bounce and re-entrainment of the particles. Sanding the models altered the local deposition profile in an uncontrolled way and is therefore not recommended for future experiments. The best overall match between the in vitro results and CFD simulations was the coated experimental geometry and coarse wall roughness simulations. For this case, the relative error between the experiments and simulations for total deposition was 6%. On a local deposition basis, cumulative lines of deposition fraction in the x and y-directions showed reasonable agreement between the experiments and simulations. However, some evidence of post-deposition particle rolling or spreading was observed with the coated experiments at the second bifurcation. Comparing experimental and CFD results cell by cell, higher maximum deposition enhancement factors (DEFs) were observed for the in vitro cases, perhaps due to factors not included in the CFD simulations. This result implies that previously predicted maximum DEF values from CFD simulations may be conservatively low and that actual values with in vitro models or in vivo may be even higher than predicted. In conclusion, this study provides a valuable new dataset for understanding the effects of surface characteristics on local deposition, assessing hotspot magnitude in the tracheobronchial airways, and validating CFD predictions. (C) 2013 Elsevier Ltd. All rights reserved.