摘要
采用原子力显微镜与小角X射线散射分析了单缸柴油机排气颗粒的结构和力学特征.结果表明:柴油机排气管温度为514、310和105,℃测点时,颗粒的黏附力分别为3.75、4.11和4.38,n N,黏附能为1.63×10-16、1.68×10-16和1.79×10-16,J.排气颗粒的力学特征差异明显,颗粒间吸引、黏连作用增强,颗粒的黏附力Fad与黏附能Wad增大,能量势垒升高.颗粒的散射强度减弱,散射曲线凸起区域特征矢量值qT与qmin减小,团聚体尺寸增大,截面平均孔径、轴向长度、回转半径和分布分维数减小,孔隙数量浓度和孔径减小.可以看出,排气颗粒当量粒径的增大导致颗粒间吸引作用增强;随着排气管温度的降低,有机物与水分不断吸附,颗粒团聚体的孔隙数量浓度、散射特征矢量和孔隙半径等空间结构参数减小,颗粒紧密团聚,致密度增大.
The atomic force microscopy and small angle X-ray scattering were used to study the interaction force and its space structure of exhaust particles, which were collected during the exhaust process of a single cylinder diesel engine at the exhaust temperature of 514 ℃, 310 ℃ and 105 ℃, respectively. The results show that, in the direction of the exhaust flow with the decreasing temperature, the attraction force, the adhesion force and the adhesion energy of the particles on the AFM probe are increased. The interaction and adhesion between the particles is enhanced and the energy barrier between particles is increased. The scattering intensity of the collected particles is weakened, the characteristic vector values qT and qmin of the scattering curve are decreased, and the size of the aggregates in- creases. Furthermore, the average pore size, the axial length, the radius of rotation and the fractal dimension of the distribution obviously decrease. At the same time, the concentration, the size of pores and the defects of the agglom- erated particles are reduced. The certain relation between the mechanical properties of the exhaust particles and the spatial structure is obtained by using the ＂rain-max＂ normalization function. The equivalent size of particles increases, so that the interaction among the particles is enhanced. Meanwhile, the accumulation of organic matter and moisture in the exhaust gas aggravated the agglomeration and shrinkage of the particles, so that the spatial struc- ture parameters such as the concentration of the pores, the scattering characteristic vector and the pore radius decrease, the particles are closely agglomerated and the density increases.
作者
赵怀北
王忠
刘帅
李瑞娜
冯渊
Zhao Huaibei1, Wang Zhong1, Liu Shnai1, Li Ruina1, Feng Yuan2(1. School of Automotive and Traffic Engineering, Jiangsu University, Zhenjiang 212013, China; 2. School of Automotive and Traffic, Wuxi Institute of Technology, Wuxi 214121, Chin)
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2018年第2期120-126,共7页
Transactions of Csice
基金
国家自然科学基金资助项目(51776089)
关键词
柴油机
排气颗粒
力学特征
空间结构
diesel engine
exhaust particle
mechanical characteristics
spatial structure
