基于EDEM-CFD的柴油机DPF孔道内积碳层堵塞特性研究  

Blockage characteristics of soot cake layers in the DPF channel of diesel engine based on EDEM-CFD

作　　者：张韦 孟丽苹 李泽宏 陈朝辉 白宇麒 张翔宇 Zhang Wei;Meng Liping;Li Zehong;Chen Zhaohui;Bai Yuqi;Zhang Xiangyu(Faculty of Transportation Engineering,Yunnan Key Laboratory of Internal Combustion Engine,Kunming University of Science andTechnology,Kunming 650500,China)

机构地区：[1]昆明理工大学交通工程学院,云南省内燃机重点实验室,昆明650500

出　　处：《农业工程学报》2022年第16期51-60,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(52166007);云南省大学生创新创业训练计划项目(2021106740025,20211067400114)。

摘　　要：为探究柴油机颗粒捕集器(Diesel Particulate Filter,DPF)内部积碳层运动引起的堵塞故障,该研究采用积碳层运动与分布可视化试验,并结合离散单元法(E-Discrete Element Method,EDEM)与计算流体动力学(Computational Fluid Dynamics,CFD),分别对对称、非对称(ACT)结构D型及O型3种DPF孔道内部的流场压降、积碳层运动及堵塞特性进行分析。结果表明:3种结构的DPF进气孔道中心流速相差较小,但排气孔道中心流速相差较大,ACT结构O型排气孔道的出口流速最快,比对称结构快47 m/s;ACT结构O型的静压差最大,是ACT结构D型静压差的1.4倍,是对称结构的3.3倍;在3种结构的DPF进气孔道中,90%以上的积碳层发生了运动,对称结构的堵塞最严重,在进气孔道前、中、后段均形成了堵塞;ACT结构D、O型DPF的堵塞程度较轻,在进气孔道中、后段形成堵塞,且O型堵塞情况好于D型;积碳层密度越大,堵塞位置越靠近进气孔道入口端,导致进气孔道的有效空间减少;积碳层密度越大,进气孔道内的最大堵塞密度反而减小,表明气体通过堵塞段的流通性能有所改善。相比之下,对称结构DPF的孔道堵塞虽严重,但未经碳加载时的静压差小于2.4 kPa,而ACT结构的孔道堵塞程度轻,静压差却极大,D型最高可达6.3 kPa、O型可达9.1 kPa。研究结果可为解决DPF孔道堵塞问题提供理论依据与工程指导。Blockage failure can be caused by the motion of the soot cake layer in the Diesel Particulate Filter(DPF).In this study,the motion and distribution of the soot cake layer were visualized to combine the E-Discrete Element Method(EDEM)with Computational Fluid Dynamics(CFD).An analysis was made on the flow field pressure drop,soot cake layer motion,and blockage characteristics inside the symmetric,asymmetric cell technology(ACT)D type and O type DPF channels.The results show that there was a small velocity difference between the inlet channel centers of the above three types of DPF.By contrast,a large difference was found in the flow velocity between the centers of the exhaust channel.Among them,the fastest flow velocity was at the outlet of the channel of the ACT structure O type,whereas,the slowest of the symmetrical structure was a difference of 47 m/s.The differential static pressure of different models of DPF also varied widely at the same time.The largest difference was observed in the static pressure of ACT structure O type,which were 1.4 and 3.3 times those of D type and the symmetric structure.More than 90%of the soot cake layer was migrated in the three types of DPF inlet channels.The most serious blockage was in the symmetric channel,with the blockage segments formed in the front,middle and back sections.The nearest distance was 41.4 mm between the blockage segment and the inlet end.The ACT structure D/O type DPF presented a relatively light blockage,where the blockages were formed in the middle and back sections of the inlet channel.Among them,the blockage was closer to the back end in the O type channel.The blockage segment was separated from the entrance 164.4 mm away from the inlet,which caused the smaller back pressure to increase.In the same type of DPF,the 550 kg/m3 high-density soot cake layer presented a greater resistance to exercise,and the blockage segment was located close to the inlet end of the inlet channel,resulting in the less effective space in the inlet channel.The blockage segment of

关 键 词：柴油机 EDEM CFD 颗粒捕集器 积碳层 堵塞特性 

分 类 号：TK442.5[动力工程及工程热物理—动力机械及工程]