Computational fluid dynamics investigation of particle intake for nasal breathing by a moving body

Particle intake by human breathing is important for developing relevant estimates of exposure in the indoor environments; however, relatively few studies are devoted to the influence from human activities. This study evaluates the nasal inhalability of micron particles for a manikin in motion by transient computational fluid dynamics (CFD) simulations. The model was built using a full-scale manikin with key facial features at the nose and mouth. The manikin was moving at a speed of 0.8 m/s through stagnant air in an indoor environment achieved by dynamic mesh. Three nasal inhalation rates of 15, 27, and 40 LPM (litres per minute) and four particle sizes (7, 22, 52, and 82 μm) were considered. The particle intake fraction was calculated to quantify the nasal inhalability of particles over different conditions. Fluid flow field of the motion-induced wake flow and particle trajectories were visualized to reveal the principles of the particle inhalability for a body in motion. This study quantifying the particle intake for a moving manikin will help to characterize a more holistic scenario for respiration modellings and developing estimates of exposure affected by human activities.