雾化治疗中气溶胶在深层肺泡输运特性的数值模拟

Objective: Based on computational fluid dynamics (CFD) method, the air and aerosol transport in a single alveolus were simulated to study the characteristics of airflow and aerosol transport in deep alveolus. Methods: A long straight duct with a hemispherical wall at one end which had periodic expansion/contraction were regarded as simplified approximation of a single alveolus. Based on this, a two-dimensional (2D) mathematical model was established.The Euler-Euler method was used to solve the transport equations of airflow and aerosol particles in the alveolus considering air diffusion along the hemisphere boundary. Results: The composition ratio of the air in the duct changed in a stable periodic way during the whole breathing process.The aerosol transport in the duct mainly depended on the particle diffusion coefficient. The advection transport had only a small effect on it. The diffusion velocity and depth of aerosol increased when the particle size decreased, especially when the particle size was smaller than 4 μm. The increase of respiratory frequency and amplitude could significantly improved the transport capacity of aerosol particles. Conclusions: In atomization treatment, aerosol particles with smaller particle size have better transportation and curative efficacy. Deep breathing should be encouraged to improve particle transport.