DPF孔道内流场及微粒沉积特性的数值模拟
Numerical Simulation for Flow and Soot Accumulation in the Channels of Diesel Particulate Filter

通过Fluent 软件建立了柴油机微粒捕集器(diesel particulate filter，DPF)计算模型，运用离散相模型模拟计 算了孔道内部气体与微粒的流动，并针对不同壁面渗透率及滤饼层厚度进行了研究．结果表明：沿DPF 长度方向， 进气孔道内气流速度逐渐降低，排气孔道内气流速度逐渐增大，壁面渗流速度也逐渐增大；渗透率的增大会加剧 DPF 孔道内速度的变化，同时引起进气孔道内静压下降，但对排气孔道静压影响不大；微粒在DPF 孔道内分布具 有不均匀性，后端沉积较多而前端较少；随着滤饼层厚度的增加，微粒分布不均匀性逐渐降低，压降受DPF 进气流 速的影响则逐渐增大．
A calculation model of diesel particulate filter(DPF)was established using the software Fluent. The flow of air and particulate matter(PM)in the channels were simulated and calculated using discrete phase model(DPM)under the condition of different permeabilities and soot thicknesses. The results show that the velocity profile decreases along the inlet channels of DPF，and increases along the outlet channels；wall flow velocity also increases along the axial direction；the increase of permeability intensifies the change of velocity，decreasing the static pressure along the inlet channels at the same time，with no significant effect on the static pressure along the outlet channels. Meanwhile the soot distribution is uneven along the channels，and the back end of DPF contains a higher soot load than the front. As the soot cake thickness increases，the unevenness of soot distribution is reduced and the pressure drop changes more significantly as a function of the inlet velocity of DPF