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目的通过数值模拟方法研究人呼吸过程中吸入的颗粒物在呼吸道内的沉积规律及其影响因素。方法建立正常人呼吸道三维数值模型,模拟吸气过程中气流在呼吸道内的分布规律。在鼻孔或口等气流入口处释放颗粒,模拟悬浮颗粒物随着吸入气流在呼吸道内的沉积过程。同时改变颗粒物直径、密度、呼吸气流速率等参数,通过对比分析,研究颗粒物在呼吸道内沉积的影响因素。结果颗粒物在呼吸道内主要沉积在鼻阈、固有鼻腔气道中部、鼻咽部以及支气管内壁,并且颗粒物的沉积率随着其直径、密度、呼吸气流速率的增大而增加,几个参数对沉积率的影响程度也不相同。结论颗粒物在呼吸道内主要沉积在气道几何形状复杂或者气道走向剧烈改变的位置,颗粒物的直径、密度、呼吸气流速率均会影响到其在呼吸道内的沉积率。研究结果可为空气污染引发呼吸道疾病风险的临床评估提供数值依据。
Objective To study the deposition law and its influencing factors of inhaled particles in the respiratory tract by the numerical simulation method. Methods The normal three-dimensional numerical model of respiratory tract was established to simulate the distribution of airflow in the respiratory tract during inhalation. Particles are released at the inlet of the nostril or mouth and simulate the deposition of suspended particles with the inhalation flow in the respiratory tract. At the same time, parameters such as particle diameter, density and respiratory flow rate were changed. By comparative analysis, the influencing factors of particulate matter deposition in the respiratory tract were studied. Results Particulate mainly deposited in the nasal passages in the respiratory tract, the inherent nasal airway, nasopharynx and bronchial wall, and the sedimentation rate of particles increased with the increase of its diameter, density and respiratory flow rate, and several parameters of deposition The rate of influence is not the same. Conclusions Particulate matter mainly resides in the respiratory tract where the geometry of the airway is complex or the airway changes drastically. The diameter, density and respiratory rate of the particulate matter all affect the deposition rate in the respiratory tract. The results provide a numerical basis for the clinical assessment of the risk of respiratory diseases caused by air pollution.