非对称孔结构对柴油机颗粒捕集器压降特性的影响

Pressure Drop Characteristics Through DPF with Different Channel Width Ratios

运用AVL Boost软件建立了柴油机颗粒捕集器(DPF)模型,研究不同排气流量、温度及碳烟与灰分沉积量对非对称孔结构DPF压降特性的影响,并着重研究不同比例孔结构压降特性的差异.结果表明:排气质量流量增大,入口温度增大,不同比例孔结构的压降敏感性增大;当DPF内碳烟沉积量较少时,通过DPF的压降随着进/出口孔比例的增加而增大;随着碳烟沉积量的增多,进口较小的DPF结构压降升高率大;灰分在DPF壁面上的层状分布可以有效阻止碳烟深层捕集模式,降低DPF压降;使用非对称孔结构可以有效提高碳烟和灰分容量,降低DPF使用后期压降并延长DPF使用寿命.

Investigating the pressure drop characteristics of asymmetric cell technology(ACT)design filter with varied inlet mass flow rates,temperature soot loads and ash loads by using 1-D computational fluid dynamics(CFD)method.The model was established by AVL Boost code. The DPFs with different inlet to outlet channel width ratios were investigated to determine the effect of soot and ash interaction on pressure loss,as well as the optimal structure for practical applications. Results show that pressure drop sensitivity at different inlet/outlet channel width ratios increases with the increased inlet mass flow rate and inlet temperature. When a small quantity of soot is deposited inside the DPF,pressure drop increases for the bigger inlet. As the filters accumulate the soot,the pressure drop increases slightly for the bigger inlet. Ash deposited on inlet channel walls of DPF prevents deep soot filtration and results in smaller pressure drop compared with the symmetric channel structure. ACT design filter can improve soot and ash capacity,reduce the pressure drop at higher soot and ash load,and prolong DPF service life.