可吸入颗粒物在不同阻塞性呼吸道内运动与沉积特性

为弄清颗粒污染物在慢性阻塞性肺病工人呼吸道内运动和沉积规律，采用数值方法讨论了2类阻塞性呼吸道内气固流动特性，分析了阻塞率（α）、阻塞位置、劳动强度等因数对流场分布、颗粒沉积形式和沉积率的影响.结果表明，α越大，病人局部缺氧越严重，当α=0.8时，相对缺氧率可达90%以上；劳动强度越强或受阻塞位置越深，病人发生哮喘的可能性愈高.呼吸道变形不会改变颗粒的沉积机制，但对其沉积形式有显著影响.α增大，劳动强度增强，粒径变大，均会导致颗粒沉积分布不对称性提高，且下呼吸道粒子沉积分布对称性更好.此外，呼吸道变形使总沉降率（η_t）减小，且α越大，η_t越小.发现对于低劳动强度，下呼吸道或者d_p>5μm的大颗粒，α对η_t影响要更为显著.

Transport and deposition characteristics of inhalable particulate matters in different obstructive airways

In order to figure out the movement and deposition of particles in the respiratory tract of workers with chronic obstructive pulmonary disease, the numerical simulations were performed to study the gas-solid flow characteristics in two types of obstructive airways. Also, the effects of the following parameters, such as obstructive rate (α), lesion location and labor intensity on flow field, particle deposition pattern and deposition efficiency were analyzed. Results indicated that the greater alpha was, the more severe the local anoxia was. When α = 0.8, the relative oxygen deficit was larger than 90%, and the stronger the labor intensity or the deeper the blocking position, the higher the possibility of asthma. Respiratory tract deformation did not change the deposition mechanism of particles, but but had a significant effect on its deposition pattern. The asymmetry of particle deposition distribution enhanced with the increasing α, the labor intensity and particle size, of which was better in lower respiratory tract. Moreover, the respiratory tract deformation reduced the total sedimentation rate (η_t), and the larger α, the smaller η_t. It was also found that α had a more significant effect on η_t for lower labor intensity, lower respiratory tract or particle diameter larger than 5μm.