Characterizing particle deposition in physiologically realistic airways and the influence of BMI: a combined experimental and computational study

This study presents the transport and particle deposition mechanisms in physiologically realistic airways and elucidates the effects of particle size bands using a combined numerical and experimental approach. Two 3D models of the human pharynx were reconstructed from MRI images of subjects with a high and a low body mass index (BMI). CFD simulations using discrete phase modelling and polydisperse particles were performed using two transient flow profiles at peak flow rates of 40 and 80 L/min. Particle image velocimetry (PIV), cascade impaction (CI) and high-performance liquid chromatography (HPLC) were used to both validate and complement the CFD data. Results demonstrate that the human pharynx associated with different BMI produces dissimilar particle dispersion behaviour, and that the spatial distribution of particles along cross sections of the airway is asymmetrical, which is more pronounced in narrower airways such as those commonly associated in humans with high BMI. The narrower pharynx also has approximately twice as much deposition than the pharynx associated with the low BMI subject for mannitol dispersed under low inspiratory flow conditions (e.g., PIFR = 40 L/min).