Three-dimensional Simulation of Heat and Moisture Transfer in the Human Bronchial Tree

A mathematical model of heat and mass transfer in human airways has been developed. Three-dimensional calculations of the distribution of heat and humidity of inhaled air in the human bronchial tree have been performed. The modeling has been performed on the basis of the analytical model of the complete bronchial tree developed earlier by the authors by the numerical method of stage- by-stage calculation. A comparison with experimental data on heat transfer in lungs shows that the model describes the change in the air temperature along the bronchial branch quite well. The process of breathing with a heated helium-oxygen mixture has been considered. This mixture is used to treat patients with bronchial asthma and COVID-19. It has been shown that the temperature of the heated helium-oxygen mixture in human lungs decreases faster than that of heated air. The results show that the thermal effect is observed not in the entire human bronchial tree, but only in the upper airways.