Inhalational Particle Movement And Deposition Numerical Simulation In The Human Upper Respiratory Tract

Atmospheric pollution is the most serious environmental problem which human are faced with. And aerosol which include various solid or liquid particle are formed with dust, soot and smog, is the main reason of atmospheric pollution. According to particle diameter, there are three kinds can be divided. When dp≤ 100μm, it is named TSP. Or when dp≤10μ m, it is named inhalational particle(PM10). And when dp≤2.5 μm, it is named micro-particle(PM2.5). Among these three kinds of aerosol, inhalational particle not only can stay in atmosphere from several days to some dozens of days, but also can float to another field ranged from several kilometres to thousands of kilometres. Inhalational particle do not be down to the earth by gravity effect, and particle surface were surrounded with various poisonous matters. So inhalational particle is not only to the function of the visibility and weather, but also contain great influence to human body health. There could be lead to respiratory inflammation, chronic bronchitis, bronchia asthma and other respiratory disorders, even to lung cancer and heart blood vessel diseases, if inhalational particle came into human body through respiration tract. Thus, the study of inhalational particle movement and deposition in human respiratory tract, therefore, may provide important information for therapeusis, toxicology and risk assessment protocols for human healthiness. But few study has been done untill today.Based on various physical models of the human upper respiratory tract, a new entire three-dimensional geometry from mouth, pharynx, larynx, trachea to triple bifurcation, which united an idealized mouth-throat model geometry developed at ARLA(Aerosol Research Laboratory of Alberta) with Weibel's lung model A, was proposed in this study. To solve the primary flow under the steady respiration and unsteady respiration that each include three kinds of breathing intensity(Q=30L/min, Q=60L/min and Q=90L/min), RNG k-e turbulence model and LES turbulence model are respectively used. Particles are traced in the Lagrangian frame at the same time. Inhalational particle deposition efficiency obtained from numerical simulation show relatively good agreement when compared with the experimental data. And the numerical simulation results show that inhalational particle deposition efficiency lies on breathing intensity, size of particle and inertia of particle.The main contents of the dissertation include the following four aspects: firstly, based on the thoroughly review and summary various human upper respiratory tract models then establish a more reasonable entire three-dimensional model from mouth to upper three bronchi; Secondly, to draw the conclusion of which turbulence model ismore fit to solve the flow field in human upper respiratory tract, two kinds of turbulence models are used and calculated inhalational particle deposition efficiency then compared to experimental data; Thirdly, through analysed the flow field in inspiration and exhalation, gets the characterictic of flow in respiratory tract; And finally, obtained the main factor which influence inhalational particle deposition by summarizing particle deposition status in human upper respiratory tract.