【摘要】 从孔隙、壁面两个维度，搭建汽油机颗粒捕集器(GPF)的动态捕集模型，考虑了多孔介质孔隙率径向不均匀，从捕集机制和微观尺寸的角度研究GPF内部结构变化对颗粒捕集性能的影响．结果表明：GPF的捕集机制主要是布朗扩散和拦截捕集，分别对应小粒径(<30 nm)和大粒径(>200 nm)的颗粒物捕集．当GPF中平均孔径减小或孔径方差增加，直径小于10μm收集器的比例增加，使得更多收集器对10～300 nm范围颗粒物的捕集效率为50%以上，进而导致GPF总捕集效率增加．经过20 min颗粒捕集，GPF捕集效率不断增大，颗粒物主要附着在孔隙率最低处，进一步降低孔隙率，但此时布朗扩散和拦截捕集效率略有降低，因而动态捕集过程中捕集效率主要受孔隙率影响．更多还原

【Abstract】 A dynamic filtration model of the gasoline particulate filter(GPF) was developed,considering both pore and wall scales,with the addition of radial porosity heterogeneity in the porous media. The impact of internal structural changes in the GPF on particle filtration performance was investigated from the perspectives of filtration mechanisms and microscopic size. It is found that the primary filtration mechanisms in the GPF are Brownian diffusion and interception,which correspond to the filtration of small particles(<30 nm) and large particles(>200 nm),respectively. When the mean pore size in the GPF decreases or the pore size variance increases,the proportion of collectors with diameters smaller than 10 μm increases. This results in a higher number of collectors achieving more than 50% filtration efficiency for particles in the range of 10—300 nm,thereby enhancing the total filtration efficiency of the GPF. After 20 minutes of particle filtration,the filtration efficiency of GPF increases and the particles adhere to the area of the lowest porosity,where the porosity reduces. However,the efficiency of Brownian diffusion and interception slightly decreases,indicating that porosity plays a dominant role in influencing filtration efficiency during the dynamic filtration process.更多还原