Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Identification of probabilistic size of breathing zone during single inhalation phase in semi-outdoor environmental scenarios
https://orcid.org/0009-0006-4484-3183
https://orcid.org/0000-0002-6553-6936
https://orcid.org/0000-0002-7715-7896
Abstract This study investigates outdoor public health by predicting the airflow fields and probabilistic size of breathing zones. Computational fluid dynamics (CFD) simulations were performed in a simplified semi-outdoor domain, utilizing a validated computer-simulated person (CSP) with an integrated nasal cavity. The simulations were conducted for eight wind orientations (0°, 90°, 180°, 270°, 45°, 135°, 225°, and 315°), four wind velocities (U ref = 0.25, 0.5, 0.75, and 1.0 m/s), and one inhalation flow rate (18.7 L/min), considering both steady and transient conditions. The RANS-based equations were solved using the SST k-omega turbulence model. Breathing zones were computed and visualized using the scale for ventilation efficiency 5 (SVE5) and reverse time-traced vector techniques. The results indicated that wind orientation influenced the air velocity, temperature, and breathing zone distribution. The steady-state condition tended to overestimate breathing zones, whereas, under transient conditions, they assumed a semi-cylindrical form that extended horizontally, with a slight slope from the nostrils towards the direction of the wind source. The horizontal extension of the breathing regions increased at high wind speeds and with a smaller cylinder radius compared to calm conditions. Eventually, this study proposed new definitions of the breathing zone in the semi-outdoor environment in different SVE5 values. These findings can contribute to air quality management and aid in assessing the probability of airborne transmission in public spaces.
Highlights The airflow field and breathing zones in semi-outdoor environment were predicted using CFD simulations. A new definition of breathing zones was provided under transient breathing conditions. The wind orientation influences the size and configuration of breathing zones. Outdoor wind velocity and breathing conditions affect the probabilistic size of breathing zones.
Identification of probabilistic size of breathing zone during single inhalation phase in semi-outdoor environmental scenarios
https://orcid.org/0009-0006-4484-3183
https://orcid.org/0000-0002-6553-6936
https://orcid.org/0000-0002-7715-7896
Abstract This study investigates outdoor public health by predicting the airflow fields and probabilistic size of breathing zones. Computational fluid dynamics (CFD) simulations were performed in a simplified semi-outdoor domain, utilizing a validated computer-simulated person (CSP) with an integrated nasal cavity. The simulations were conducted for eight wind orientations (0°, 90°, 180°, 270°, 45°, 135°, 225°, and 315°), four wind velocities (U ref = 0.25, 0.5, 0.75, and 1.0 m/s), and one inhalation flow rate (18.7 L/min), considering both steady and transient conditions. The RANS-based equations were solved using the SST k-omega turbulence model. Breathing zones were computed and visualized using the scale for ventilation efficiency 5 (SVE5) and reverse time-traced vector techniques. The results indicated that wind orientation influenced the air velocity, temperature, and breathing zone distribution. The steady-state condition tended to overestimate breathing zones, whereas, under transient conditions, they assumed a semi-cylindrical form that extended horizontally, with a slight slope from the nostrils towards the direction of the wind source. The horizontal extension of the breathing regions increased at high wind speeds and with a smaller cylinder radius compared to calm conditions. Eventually, this study proposed new definitions of the breathing zone in the semi-outdoor environment in different SVE5 values. These findings can contribute to air quality management and aid in assessing the probability of airborne transmission in public spaces.
Highlights The airflow field and breathing zones in semi-outdoor environment were predicted using CFD simulations. A new definition of breathing zones was provided under transient breathing conditions. The wind orientation influences the size and configuration of breathing zones. Outdoor wind velocity and breathing conditions affect the probabilistic size of breathing zones.
Identification of probabilistic size of breathing zone during single inhalation phase in semi-outdoor environmental scenarios
https://orcid.org/0009-0006-4484-3183
https://orcid.org/0000-0002-6553-6936
https://orcid.org/0000-0002-7715-7896
Abstract This study investigates outdoor public health by predicting the airflow fields and probabilistic size of breathing zones. Computational fluid dynamics (CFD) simulations were performed in a simplified semi-outdoor domain, utilizing a validated computer-simulated person (CSP) with an integrated nasal cavity. The simulations were conducted for eight wind orientations (0°, 90°, 180°, 270°, 45°, 135°, 225°, and 315°), four wind velocities (U ref = 0.25, 0.5, 0.75, and 1.0 m/s), and one inhalation flow rate (18.7 L/min), considering both steady and transient conditions. The RANS-based equations were solved using the SST k-omega turbulence model. Breathing zones were computed and visualized using the scale for ventilation efficiency 5 (SVE5) and reverse time-traced vector techniques. The results indicated that wind orientation influenced the air velocity, temperature, and breathing zone distribution. The steady-state condition tended to overestimate breathing zones, whereas, under transient conditions, they assumed a semi-cylindrical form that extended horizontally, with a slight slope from the nostrils towards the direction of the wind source. The horizontal extension of the breathing regions increased at high wind speeds and with a smaller cylinder radius compared to calm conditions. Eventually, this study proposed new definitions of the breathing zone in the semi-outdoor environment in different SVE5 values. These findings can contribute to air quality management and aid in assessing the probability of airborne transmission in public spaces.
Highlights The airflow field and breathing zones in semi-outdoor environment were predicted using CFD simulations. A new definition of breathing zones was provided under transient breathing conditions. The wind orientation influences the size and configuration of breathing zones. Outdoor wind velocity and breathing conditions affect the probabilistic size of breathing zones.
Identification of probabilistic size of breathing zone during single inhalation phase in semi-outdoor environmental scenarios
Abouelhamd, Islam (Autor:in) / Kuga, Kazuki (Autor:in) / Yoo, Sung-Jun (Autor:in) / Ito, Kazuhide (Autor:in)
Building and Environment ; 243
27.07.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Computational study of breathing methods for inhalation exposure
| Taylor & Francis Verlag | 2011
| Wiley | 2022