Purpose: Computational Fluid Dynamics (CFD) simulations are performed to investigate the impact of adding a grid to a two-inlet dry powder inhaler (DPI). The purpose of the paper is to show the importance of the correct choice of closure model and modeling approach, as well as to perform validation against particle dispersion data obtained from in-vitro studies and flow velocity data obtained from particle image velocimetry (PIV) experiments. Methods: CFD simulations are performed using the Ansys Fluent 2020R1 software package. Two RANS turbulence models (realisable $k - \epsilon$ and $k - \omega$ SST) and the Stress Blended Eddy Simulation (SBES) models are considered. Lagrangian particle tracking for both carrier and fine particles is also performed. Results: Excellent comparison with the PIV data is found for the SBES approach and the particle tracking data are consistent with the dispersion results, given the simplicity of the assumptions made. Conclusions: This work shows the importance of selecting the correct turbulence modelling approach and boundary conditions to obtain good agreement with PIV data for the flow-field exiting the device. With this validated, the model can be used with much higher confidence to explore the fluid and particle dynamics within the device.

中文翻译：

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使用计算流体动力学（CFD）建模设计改进的干粉吸入器

目的：进行计算流体动力学（CFD）模拟，以研究将网格添加到两入口干粉吸入器（DPI）中的影响。本文的目的是说明正确选择闭合模型和建模方法的重要性，并对从体外研究获得的颗粒分散数据和从颗粒图像测速（PIV）实验获得的流速数据进行验证。方法：使用Ansys Fluent 2020R1软件包执行CFD模拟。考虑了两个RANS湍流模型（可重复使用的$ k-\ epsilon $和$ k-\ omega $ SST）和应力混合涡模拟（SBES）模型。还对载体和细颗粒都进行了拉格朗日粒子跟踪。结果：在假定简单的前提下，对于SBES方法，可以发现与PIV数据具有出色的比较，并且粒子跟踪数据与分散结果一致。结论：这项工作表明选择正确的湍流建模方法和边界条件以与离开设备的流场的PIV数据取得良好一致性的重要性。通过验证，可以更可靠地使用该模型来探索设备内的流体和颗粒动力学。