This study presents the results of numerical simulations for airflow field and particle dispersion and deposition around a mannequin standing inside a ventilated room.  A 3-D airway model was constructed from the nostril inlet to the end of 4th lung generation and was integrated into the standing mannequin model in the room. The computational domain includes the region around the mannequin and inside the respiratory system. The room is ventilated by an air-conditioning system that supplies air with a speed of 3m/s from a diffuser mounted on the top of the sidewall and exits from a damper mounted at the bottom of the side or front wall. In the first mode the diffuser and damper located on the wall in front of the mannequin and in the second mode on the wall at the right side of the mannequin. The mean airflow field inside the room was obtained by solving the Navier-Stokes and continuity equations using the Ansys-Fluent software. The k- SST transitional model was employed for turbulence modeling. Then, spherical particles with 5, 10, 20, 40, and 60 µm diameter and unit density were released into the room and their trajectories were tracked by using the Lagrangian trajectory analysis approach. Aspiration efficiency and particle deposition for inhalation flow rates of 15 and 30 lit/min were analyzed by means of the improved discrete random walk (DRW) stochastic model using a user-defined function (UDF) coupled into the Ansys-Fluent discrete phase model. Simulation results for the mean airflow showed the formation of a large recirculation zone inside the room. In the first mode, the main recirculation zone formed behind mannequin that carried the flow streamlines toward the mannequin breathing zone.  In the second mode, the recirculation formed in front of the mannequin face that led the streamlines out of the breathing zone. The simulation results for particle inhalation showed that the aspiration efficiency of particles is higher in the first ventilation mode compared to the second mode. The results also showed that the total deposition of particles in the room increases as particle size increases. In addition, the regional deposition of particles inside the respiratory system was presented for both ventilation modes and discussed.  


Particle Transport and Deposition in a Ventilated Room With a Standing Mannequin

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

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