Numerical investigation of turbulent airflow and microparticle deposition in a realistic model of human upper airway using LES

The Large Eddy Simulation (LES) technique was used to study the turbulent airflow field in a realistic model of human upper airways from nostril to the end of trachea. The Lagrangian approach was used to calculate the trajectories and deposition of micro-particles for the breathing rates of 30 and 60 l/min. While the LES is inherently unsteady, the cases of inhalation breathing with a constant mean airflow velocity were simulated. The present LES results are compared with those obtained from the earlier RANS model study. In the RANS model the effect of airflow turbulence velocity fluctuations on particle trajectories was modeled using the Continuous Random Walk (CRW) stochastic model. It was found that the results obtained by the LES method for the total depositions of micro-particles are comparable with those of the RANS model. The regional particle deposition, however, showed marked differences. In addition, significant differences were found in the predicted airflow characteristics. (C) 2017 Elsevier Ltd. All rights reserved.