Mathematical modeling of airflow in the airways when breathing through mouth

• Main Authors: Trusov, Peter V., Zaitseva, Nina V., Tsinker, Mikhail Yu, Svintsova, Polina D.
• Format: Conference Proceeding
• Language: English
• Subjects: Air flow; Breathing; Larynx; Mathematical models; Mouth; Respiration; Respiratory system; Trachea; Turbulent flow
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0224811

As part of the creation of a mathematical model of the human respiratory system, the geometry of the airway section from the oral cavity to the trachea was built; using the constructed geometry, the study of the unsteady air flow during breathing through the mouth was performed. The airways were modeled as a curved channel with a variable circular cross section. Airflow is described with a viscous liquid model and we highlight the necessity to consider its turbulent nature. To do that, we used the k-ω model. Characteristics of airflow in the airways from the oral cavity to the trachea were calculated in Ansys CFX. As a result, we obtained inhaled airflow velocities at different moments. The highest airflow velocities occurred at the points where the airways became narrower: near the soft palate (approximately 10 m/sec) and the larynx (the narrowest section where an airflow velocity reaches 13.47 m/sec). During an inhale, an airflow volume varies from 0 to 58.4 l/min at the entry to the oral cavity. This corresponds to different types of respiration and airflow: airflow less than 15 l/min is laminar; from 15 to 30 l/min, transitional; incoming airflow, which is higher than 30 l/min, is turbulent. The results regarding airflow velocities and the nature of airflow are fully consistent with data obtained by other researchers. The further development of the model involves joint modeling of airflow in the upper and lower airways and the lungs as well as modeling airflow that contains dust particles.