Computational fluid dynamics (CFD) predictions of inertial particle deposition have not compared well with data from nasal replicas due to effects of surface texture and the resolution of tomographic images. To study effects of geometric differences between CFD models and nasal replicas, nasal CFD models with different levels of surface smoothness were reconstructed from the same MRI data used to construct the nasal replica used by Kelly et al. (2004) [Aerosol Sci. Technol. 38:1063-1071]. One CFD model in particular was reconstructed without any surface smoothing to preserve the detailed topology present in the nasal replica. Steady-state inspiratory airflow and Lagrangian particle tracking were simulated using Fluent software. Particle deposition estimates from the smoother models under-predicted nasal deposition from replica casts, which was consistent with previous findings. These discrepancies were overcome by including surface artifacts that were not present in the reduced models and by plotting deposition efficiency versus the Stokes number, where the characteristic diameter was defined in terms of the pressure-flow relationship to account for changes in airflow resistance due to wall roughness. These results indicate that even slight geometric differences have significant effects on nasal deposition and that this information should be taken into account when comparing particle deposition data from CFD models with experimental data from nasal replica casts.

中文翻译：

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表面光滑度对人鼻模型惯性颗粒沉积的影响


由于表面纹理和断层扫描图像分辨率的影响，惯性颗粒沉积的计算流体动力学 (CFD) 预测与鼻腔复制品的数据无法很好地进行比较。为了研究 CFD 模型和鼻复制品之间几何差异的影响，根据 Kelly 等人用于构建鼻复制品的相同 MRI 数据重建了具有不同表面光滑度水平的鼻 CFD 模型。 (2004) [气溶胶科学。技术。 38：1063-1071]。特别是在没有任何表面平滑的情况下重建了一个 CFD 模型，以保留鼻腔复制品中存在的详细拓扑结构。使用 Fluent 软件模拟稳态吸气气流和拉格朗日粒子跟踪。较平滑模型的颗粒沉积估计低于模型复制品的鼻腔沉积预测，这与之前的发现一致。这些差异通过包括简化模型中不存在的表面伪影以及绘制沉积效率与斯托克斯数的关系图来克服，其中特征直径是根据压力-流量关系来定义的，以考虑由于壁引起的气流阻力的变化粗糙度。这些结果表明，即使是微小的几何差异也会对鼻沉积产生显着影响，并且在将 CFD 模型的颗粒沉积数据与鼻模型复制品的实验数据进行比较时，应考虑到这一信息。