School of Mechanical Engineering, The University of Adelaide, North Terrace, Adelaide, SA, 5005, Australia.
Biomech Model Mechanobiol. 2022 Jun;21(3):849-870. doi: 10.1007/s10237-022-01563-8. Epub 2022 Feb 8.
In this paper, the effect of the turbulence and swirling of the inlet flow and the diameter of the nozzle on the flow characteristics and the particles' transport/deposition patterns in a realistic combination of the nasal cavity (NC) and the maxillary sinus (MS) were examined. A computational fluid dynamics (CFD) model was developed in ANSYS® Fluent using a hybrid Reynolds averaged Navier-Stokes-large-eddy simulation algorithm. For the validation of the CFD model, the pressure distribution in the NC was compared with the experimental data available in the literature. An Eulerian-Lagrangian approach was employed for the prediction of the particle trajectories using a discrete phase model. Different inlet flow conditions were investigated, with turbulence intensities of 0.15 and 0.3, and swirl numbers of 0.6 and 0.9 applied to the inlet flow at a flow rate of 7 L/min. Monodispersed particles with a diameter of 5 µm were released into the nostril for various nozzle diameters. The results demonstrate that the nasal valve plays a key role in nasal resistance, which damps the turbulence and swirl intensities of the inlet flow. Moreover, it was found that the effect of turbulence at the inlet of the NC on drug delivery to the MS is negligible. It was also demonstrated that increasing the flow swirl at the inlet and decreasing the nozzle diameter improves the total particle deposition more than threefold due to the generation of the centrifugal force, which acts on the particles in the nostril and vestibule. The results also suggest that the drug delivery efficiency to the MS can be increased by using a swirling flow with a moderate swirl number of 0.6. It was found that decreasing the nozzle diameter can increase drug delivery to the proximity of the ostium in the middle meatus by more than 45%, which subsequently increases the drug delivery to the MS. The results can help engineers design a nebulizer to improve the efficiency of drug delivery to the maxillary sinuses.
本文研究了入口流动的湍流和旋流以及喷嘴直径对鼻腔（NC）和上颌窦（MS）真实组合中的流动特性和颗粒输运/沉积模式的影响。在 ANSYS® Fluent 中使用混合雷诺平均纳维-斯托克斯-大涡模拟算法开发了计算流体动力学（CFD）模型。为了验证 CFD 模型，将 NC 中的压力分布与文献中可用的实验数据进行了比较。使用离散相模型通过欧拉-拉格朗日方法预测了颗粒轨迹。研究了不同的入口流动条件，入口流动的湍流强度为 0.15 和 0.3，旋度为 0.6 和 0.9，流速为 7 L/min。将直径为 5 µm 的单分散颗粒释放到不同喷嘴直径的鼻孔中。结果表明，鼻阀在鼻阻力中起着关键作用，它会阻尼入口流动的湍流和旋流强度。此外，还发现 NC 入口处的湍流对药物输送到 MS 的影响可以忽略不计。研究还表明，由于在鼻孔和前庭中作用于颗粒的离心力的产生，增加入口处的流动旋度并减小喷嘴直径可以将总颗粒沉积提高三倍以上。结果还表明，通过使用中等旋度为 0.6 的旋流可以提高药物输送到 MS 的效率。研究发现，减小喷嘴直径可以将药物输送到中鼻甲口附近的效率提高 45%以上，从而增加药物输送到 MS 的效率。这些结果可以帮助工程师设计雾化器以提高药物输送到上颌窦的效率。
