摘要
为加装DOC+DPF的D30TCI柴油机搭建试验台架,进行了两种不同结构载体的压降特性试验。建立柴油机颗粒物捕集器(DPF)计算模型,研究了灰分分布系数对DPF压降和捕集特性的影响,并优化了非对称孔载体进/出口孔径比例。运用离散相模型模拟了灰分沉积和载体结构对DPF孔道内部气流运动和微粒沉积特性的影响。结果表明:DPF压降和捕集效率随灰分分布系数增大而升高,非对称孔结构载体进/出口孔径比例存在一个最佳范围(1.25~1.35)使DPF压降和捕集特性达到最优;沿DPF轴向方向,进口孔道内气流速度先升后降,出口孔道内气流速度则逐渐升高,非对称孔结构DPF的进/出口速度均高于对称孔结构;灰分累积会加剧DPF孔道内速度的变化,孔道中心处速度最高,越靠近壁面速度越低;微粒在DPF孔道内呈现后端多而前端少的不均匀分布;与非对称孔结构相比,对称孔结构DPF捕集到的颗粒数更少,而颗粒浓度分布更不均匀,但灰分累积可提高微粒分布的均匀性。
A test bench for D30TCI diesel engine with DOC+DPF is built to conduct the pressure drop characteristics test on the carriers with two different structures.The calculation model for diesel particulate filter(DPF)is established,the effects of ash distribution coefficient on the pressure drop and trap characteristics of DPF are studied,and the inlet/outlet aperture ratio of the carrier with asymmetric hole structure is optimized.The discrete phase model is used to simulate the effects of ash deposition and carrier structure on the gas flow movement in DPF channel and particulate deposition characteristics.The results show that the DPF pressure drop and trapping efficiency increase with the increase of ash distribution coefficient,and there is an optimal range(1.25~1.35)for the inlet/outlet aperture ratio of the carrier with asymmetric hole structure to achieve the optimal DPF pressure drop and trap characteristics.Along the axial direction of DPF,the gas flow velocity in inlet channel rises first and then falls,while that in outlet channel gradually increases.The inlet/outlet velocities of DPF with asymmetric hole structure are higher than that with symmetric hole structure.Ash accumulation may aggravate the change of velocity in DPF channel,which reaches the highest in the center while lowers in the vicinity of wall surface.The particulates in DPF channels exhibit an uneven distribution:more in the front-end and less in the rear-end.Compared with asymmetric hole structure,the DPF with symmetric hole structure traps less particulates with more uneven distribution in particulate concentration,but ash accumulation can enhance the evenness of particulate distribution.
作者
陈贵升
李青
吕誉
潘明章
贺如
黄震
Chen Guisheng;Li Qing;LüYu;Pan Mingzhang;He Ru;Huang Zhen(Kunming University of Science and Technology,Yunnan Key Laboratory of Internal Combustion Engine,Kunming 650500;College of Mechanical Engineering,Guangxi University,Nanning 530004)
出处
《汽车工程》
EI
CSCD
北大核心
2020年第10期1346-1353,1377,共9页
Automotive Engineering
基金
国家自然科学基金(51866004,51865002)
云南省教育厅科学研究基金(2019Y0033)
昆明理工大学分析测试基金(2019M20172106009)资助。
关键词
柴油机颗粒物捕集器
非对称孔结构
灰分
压降
流场
diesel particulate filter
asymmetric hole structure
ash
pressure drop
flow field
