This study investigated the particle adhesion mechanism in a capsule of dry powder inhaler (DPI) based on a combined computational fluid dynamics and discrete element method (CFD–DEM) approach. In this study, the Johnson–Kendall–Roberts (JKR) theory was selected as the adhesion force model. The simulation results corroborated the experimental results—numerous particles remained on the outlet side of the capsule, while a few particles remained on the inlet side. In the computer simulation, the modeled particles were placed in a capsule. They were quickly dispersed to both sides of the capsule, by air fed from one side of the capsule, and delivered from the air inlet side to the outlet side of the capsule. It was confirmed that vortex flows were seen at the outlet side of the capsule, which, however, were not seen at the inlet side. Numerous collisions were observed at the outlet side, while very few collisions were observed at the inlet side. These results suggested that the vortex flows were crucial to reduce the amount of residual particles in the capsule. The original capsule was then modified to enhance the vortex flow in the area, where many particles were found remaining. The modified capsule reduced the number of residual particles compared to the original capsule. This investigation suggests that the CFD–DEM approach can be a great tool for understanding the particle adhesion mechanism and improving the delivery efficiency of DPIs.

这项研究基于计算流体动力学和离散元方法（CFD–DEM）的组合方法，研究了干粉吸入器（DPI）胶囊中的颗粒粘附机理。在这项研究中，约翰逊·肯德尔·罗伯茨（JKR）理论被选作粘附力模型。模拟结果证实了实验结果-大量的颗粒保留在胶囊的出口侧，而一些颗粒保留在入口侧。在计算机模拟中，将建模的粒子放入胶囊中。它们通过从胶囊的一侧供给的空气迅速分散到胶囊的两侧，并从胶囊的空气入口侧输送到出口侧。证实了在胶囊的出口侧看到涡流，但是在入口侧没有看到涡流。在出口侧观察到许多碰撞，而在入口侧观察到很少的碰撞。这些结果表明，涡流对于减少胶囊中的残留颗粒数量至关重要。然后修改原始胶囊，以增强该区域的涡流，该区域发现许多颗粒残留。与原始胶囊相比，改进的胶囊减少了残留颗粒的数量。这项研究表明，CFD–DEM方法可以成为了解粒子粘附机理和提高DPI传递效率的绝佳工具。然后修改原始胶囊，以增强该区域的涡流，该区域发现许多颗粒残留。与原始胶囊相比，改进的胶囊减少了残留颗粒的数量。这项研究表明，CFD–DEM方法可以成为了解粒子粘附机理和提高DPI传递效率的绝佳工具。然后修改原始胶囊，以增强该区域的涡流，该区域发现许多颗粒残留。与原始胶囊相比，改进的胶囊减少了残留颗粒的数量。这项研究表明，CFD-DEM方法可以成为了解粒子粘附机理和提高DPI传递效率的绝佳工具。