Computational fluid dynamics simulation of full breathing cycle for aerosol deposition in trachea: Effect of breathing frequency

Abstract

Abstract Aerosols have been widely used in the treatment of certain airway diseases. With different breathing conditions of patients, the flow pattern might not cause the aerosol to transport and deposit on the desired bronchial section. In this study, computational fluid dynamics simulations based on the Euler–Euler method were successfully used to evaluate the airflow behavior when an electrostatic charge was present. The three-dimensional domain was acquired and derived from the computed tomography scan of the patient. Three breathing frequencies were investigated. The instantaneous contour plot revealed that the particles migrated to the wall since charged particles will move from the high to the low potentials. It was found that the variation of the breathing frequency plays a significant role on designated particle deposition region. At a short flow time, the particles only traveled and deposited on the upper part of the airway, whereas as the time flow increased the particles tended to increasingly accumulate on the lower parts of the airway. The electrostatic charge model for aerosol deposition has shown that the further design of aerosol transport must take an average breathing frequency into consideration. The wall shear stress, oscillatory flow velocity index, granular temperature, granular pressure and skin friction coefficient were able to imply the amount of solid particles deposited within the system. All the purposed indices can be used as preliminary indicators for indicating a potential deposition location of the aerosol.