基于分形理论和拉曼光谱的柴油机颗粒物特性

Characteristics of Diesel Particulates Based on Fractal Theory and Raman Spectrum

基于分形理论和拉曼光谱试验对柴油机排气颗粒物在不同工况下的理化特性变化规律进行研究.利用分形理论对透射电镜图进行研究发现,颗粒物分形维数处于1.58~1.87,随转速增加而变大,随负荷增加而减小;通过拉曼光谱分析发现,在高转速或低负荷工况下,颗粒物D1峰(1360 cm^-1)半高宽、ID1/IG(D1峰和G峰相对强度)与ID3/IG(D3峰和G峰相对强度)呈升高趋势.研究结果表明:低转速或高负荷下,颗粒物通常呈链状分布,颗粒物间排列相对疏松;高转速或低负荷下,颗粒物的无序度增强,容易被氧化,有利于颗粒物捕集器再生.

Based on fractal theory and Raman spectrum test,the physical and chemical characteristics of diesel exhaust particulate matter(PM)under different working conditions were studied.Fractal theory was used to study the transmission electron microscope(TEM)images,which showed that the fractal dimension of particles ranged from 1.58 to 1.87 and increased with the increase of rotating speed and decreased with the increase of load.Raman spectrum analysis showed that under high rotating speed or low load conditions,full width at half maximum(FWHM)of D1(1360 cm^-1)peak,ID1/IG(relative strength of D1 peak and G peak)and ID3/IG(relative strength of D3 peak and G peak)tended to increase.The results show that under low rotating speed or high load,the particles are usually distributed in chains,and the arrangement between particles is relatively loose.At high rotation speed or low load,the disorder degree of particulates is enhanced and it is easy to be oxidized,which is beneficial to the regeneration of particulate traps.