带电颗粒物在柴油机颗粒物检测装置中的运动特性

为了研究带电颗粒物在柴油机颗粒物检测装置中的运动特性,建立了气相、电场及颗粒物相耦合模型,以COMSOL Multiphysics软件为工具对模型求解,得到了柴油机颗粒物检测装置内部带电颗粒物的运动轨迹、速度特性及受力情况。结果表明:在电场力的作用下带电颗粒物会向接地极板方向运动,在轨迹上出现运动偏移,在电离-荷电区施加高电压,静电捕集区施加方波电压时,可在测量区出现方波电流,实现颗粒物浓度转化;在电离-荷电区和静电捕集区附近颗粒物运动速度较慢且稳定,实现了在电离-荷电区颗粒物充分荷电,并保证在静电捕集区部分颗粒物可被捕集;在电离-荷电区和静电捕集区,颗粒物受电场力和拖拽力共同作用运动,拖拽力随入口流速增加而略有增大。

Motion Characteristics of Charged Particulate Matter in Diesel Particulate Matter Detection Device

A model coupling gas phase, electric field and particle phase was established to study the motion characteristics of charged particles in a diesel particulate detection device. The model was solved by the COMSOL Multiphysics software, and the motion track and velocity of as well as the force on the charged particles inside the diesel particulate detection device were obtained. The results show that under electric field force, the charged particles move towards the grounding plate and shifted from the original track. As a high voltage is applied to the ionization-charge region, and a square wave voltage to the electrostatic trapping region, the square wave current appears in the measurement region, achieving the conversion of particle concentration. The particle motion is slow and stable near the ionization-charge and electrostatic trap regions, making particles be fully charged in the ionization-charge region, and some particles be trapped in the electrostatic trap region. In the ionization-charged and electrostatic trapping zones, particles are affected by the electric field and the drag forces, and the drag force increases to some extent with the increase of the inlet flow velocity.