柴油机微粒捕集器流通性与微粒加载特性数值模拟  

Numerical Simulation of Flow Capability and Soot Particle Accumulation Performance of Diesel Particulate Filter

作　　者：王特 黄豪中[1] 李之华 王辉[2] 黄荣 陈英杰 Wang Te;Huang Haozhong;Li Zhihua;Wang Hui;Huang Rong;Chen Yingjie(School of Mechanical Engineering,Guangxi University,Nanning 530004,China;Engineering Research Institute,Guangxi Yuchai Machinery Co.,Ltd,Yulin 537005,China)

机构地区：[1]广西大学机械工程学院,南宁530004 [2]广西玉柴机器股份有限公司工程研究院,玉林537005

出　　处：《燃烧科学与技术》2021年第3期303-312,共10页Journal of Combustion Science and Technology

基　　金：国家重点研发计划资助项目(2018YFB0105902).

摘　　要：使用AVL-Fire软件建立柴油机微粒捕集器(DPF)三维计算模型,模拟DPF内的压降损失、深层微粒沉积、滤饼层微粒沉积和总微粒沉积特性.研究不同的排气流量、排气温度、初始灰分、灰分分布和微粒分布对DPF流通性与微粒加载特性的影响.结果表明:在微粒加载过程中(考虑微粒再生的影响),DPF压降主要由壁面压降损失、微粒深层压降损失和微粒滤饼层压降损失组成,壁面压降损失呈现主要作用;当排气温度超过610 K时,壁面压降上升速率与深层压降上升速率之和大于滤饼层压降上升速率;升高排气温度和增加初始灰分,DPF压降损失增加;增加排气流量,深层微粒沉积速度和滤饼层微粒沉积速度加快,导致DPF压降损失增加;层状灰分对DPF压降损失升高作用大于堵塞段灰分;微粒在入口孔道表面呈抛物线分布(最小在DPF载体中间)时DPF压降最小;提高排气温度,有利于微粒与O_(2)进行再生反应,但C与NO_(2)反应速率没有明显变化;当排气温度升高到710 K时,深层微粒沉积量先上升后下降,滤饼层微粒沉积量先保持不变后缓慢上升.The overall pressure drop loss,deep particle accumulation,filter cake layer particle accumulation and total soot particle accumulation performance of a diesel particulate filter(DPF)were studied through numerical simulations.A 3-D computational model of DPF was built using the AVL-Fire software to investigate the effects of outlet mass flow rate,outlet temperature,initial ash content,ash distribution,and soot distribution on the DPF’s flow capability and soot particle accumulation characteristics.Results show that during the soot particle accumulation(considering the effect of particle regeneration),the overall pressure drop is mainly composed of wall pressure drop loss,deep soot particle pressure drop loss and filter cake layer soot particle pressure drop loss,among which the wall pressure drop loss plays a major role.When the outlet temperature exceeds 610 K,the sum of the wall pressure drop rate and the deep layer drop rate is greater than the filter cake layer drop rate.Increasing the outlet temperature and increasing the initial ash will increase the DPF pressure drop loss.In addition,increasing the exhaust flow rate will accelerate the accumulation rate of deep layer particles and filter cake layer particles,which results in an increase in the DPF’s pressure drop loss.Layered ash has a greater effect on the DPF’s pressure drop loss than the ash in the blocked section.When the particles are parabolically distributed on the surface of the inlet channel(the smallest is in the middle of the DPF carrier),the DPF’s pressure drop is the smallest.Increasing the outlet temperature is beneficial to the regeneration reaction of particles and O_(2),but the reaction rate of C and NO_(2) does not change significantly.When the outlet temperature rises to 710 K,the deposi-tion amount of deep layer particles first rises and then decreases,while the accumulation amount of filter cake layer particles keeps unchanged first and then rises slowly.

关 键 词：柴油机 微粒捕集器 DPF压降 深层微粒沉积 滤饼层微粒沉积 

分 类 号：TK421.5[动力工程及工程热物理—动力机械及工程]