Optimal human respiratory simulation for exhaled gas based on CFD method

• Published in: PloS one Vol. 19; no. 11; p. e0313522
• Main Authors: Gao, Feng, Li, Yanfeng, Su, Zhihe, Wang, Chunlin, Wang, Haidong, Li, Junmei
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 18.11.2024; Public Library of Science (PLoS)
• Subjects: Accuracy; Aerosols; Algorithms; Analysis; Biology and Life Sciences; Boundary conditions; Breathing; Computational fluid dynamics; Computer and Information Sciences; Computer Simulation; Diagnosis; Disease susceptibility; Evaluation; Exhalation; Exhalation - physiology; Experiments; Fluid dynamics; Fluid flow; Gases; Heat; Humans; Hydrodynamics; Indoor environments; Infectious diseases; Inhalation; Iterative algorithms; Laminar flow; Models, Biological; Neural networks; Partial differential equations; Penetration depth; Physical Sciences; Pollutants; Pollution dispersion; Research and Analysis Methods; Researchers; Respiration; Respiratory tract diseases; Risk factors; Simulation; Simulation methods; Sine waves; Software; Turbulence models; Velocity; Ventilation; Visualization; Vorticity; China
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0313522

Human breathing is crucial for studying indoor environments and human health. Computational Fluid Dynamics (CFD) is a key tool for simulating human respiration. To enhance the accuracy of CFD simulations and reduce computation time, a new simulation strategy for human respiration is proposed in this paper. The effects of steady versus unsteady boundary conditions on simulation results were examined. For the unsteady boundary, sinusoidal exhalation velocities and non-inhalation gas were assumed, while the steady boundary involved constant velocities during both exhalation and inhalation phases. The jet center trajectory under different boundary conditions was analyzed and compared with experimental data. Additionally, variations in pollutant dispersion near the mouth under the two boundary conditions were discussed. Furthermore, the paper compared the calculation accuracy, calculation time and memory occupied by a single turbulence model or switching flow character models in human respiration simulation. Differences in exhaled gas vorticity and jet penetration depth across different flow models were identified. Finally, combined with the non-iterative algorithm, the optimal strategy of human respiration simulation was proposed. Results show that under the comprehensive consideration of calculation accuracy, calculation time and memory occupancy, using sinusoidal expiratory boundary conditions combined with the PISO algorithm, with the RNG k-ε model during expiratory phase, and switching into the laminar flow during inspiratory phase, is the optimal strategy of simulating human breathing.