Farnoud Ali, Baumann Ingo, Rashidi Mohammad Mehdi, Schmid Otmar, Gutheil Eva
Comprehensive Pneumology Center, Member of the German Center for Lung Research, Max-Lebsche-Platz 31, 81377, Munich, Germany; Institute of Lung Biology and Disease, Helmholtz Zentrum München, 85764, Neuherberg, Germany; Interdisciplinary Center for Scientific Computing, Heidelberg University, 69120, Heidelberg, Germany.
Department of Otorhinolaryngology, Head and Neck Surgery, Medical Center of Heidelberg University, Heidelberg, 69120, Germany.
Comput Biol Med. 2020 Aug;123:103816. doi: 10.1016/j.compbiomed.2020.103816. Epub 2020 May 18.
Numerical simulations of the dispersion and deposition of poly-disperse particles in a patient-specific human nasal configuration are performed. Computed tomography (CT) images are used to create a realistic configuration of the nasal cavity and paranasal sinuses. The OpenFOAM software is used to perform unsteady Large Eddy Simulations (LES) with the dynamic sub-grid scale Smagorinsky model. For the numerical analysis of the particle motion, a Lagrangian particle tracking method is implemented. Two different nosepieces with clockwise inclinations of 45° and 90° with respect to the horizontal axis are connected to the nostrils. A sinusoidal pulsating airflow profile with a frequency of 45 Hz is imposed on the airflow which carries the particles. Flow partition analysis inside the sinuses show that ventilation of the sinuses is improved slightly when the 45° nosepiece is used instead of the 90° nosepiece. The flow partition into the right maxillary is improved from 0.22% to 0.25%. It is observed that a closed soft palate increases the aerosol deposition efficiency (DE) in the nasal cavity as compared to an open soft palate condition. The utilization of pulsating inflow leads to more uniform deposition pattern in the nasal airway and enhances the DE by 160% and 44.6%, respectively, for the cases with clockwise 45° and 90° nosepieces, respectively. The bi-directional pulsating drug delivery with the same particle size distribution and inflow rates as the PARI SINUS device results in higher total DEs with 45° nosepiece than with the 90°. Thus, the numerical simulation suggests that the 45° nosepiece is favorable in terms of the delivered dose.
对多分散颗粒在特定患者鼻腔结构中的扩散和沉积进行了数值模拟。利用计算机断层扫描（CT）图像创建鼻腔和鼻窦的真实结构。使用OpenFOAM软件，通过动态亚网格尺度Smagorinsky模型进行非定常大涡模拟（LES）。对于颗粒运动的数值分析，采用了拉格朗日粒子跟踪方法。两个相对于水平轴顺时针倾斜45°和90°的不同鼻部件连接到鼻孔。对携带颗粒的气流施加频率为45Hz的正弦脉动气流剖面。鼻窦内的气流分配分析表明，使用45°鼻部件代替90°鼻部件时，鼻窦的通气略有改善。进入右上颌的气流分配从0.22%提高到0.25%。观察到与软腭张开的情况相比，软腭闭合会增加鼻腔中的气溶胶沉积效率（DE）。对于顺时针倾斜45°和90°鼻部件的情况，脉动流入的使用分别导致鼻气道中更均匀的沉积模式，并使DE分别提高160%和44.6%。与PARI SINUS装置具有相同粒径分布和流入速率的双向脉动药物输送，使用45°鼻部件时的总DE高于使用90°鼻部件时。因此，数值模拟表明，就给药剂量而言，45°鼻部件更具优势。
