润湿剂促进燃油细颗粒捕集的实验研究

Experimental study on promotion of fine particles capture with wetting agents

在反应室中研究了雾化液滴与燃油细颗粒的相互作用机制。提出了一种润湿剂对细颗粒捕集促进的新方法,用于研究颗粒与液滴作用前后颗粒数浓度和粒径分布变化特性及细颗粒的捕集特性。采用电称低压冲击器(ELPI)在线测试分析颗粒数浓度和粒径分布特性,用SEM和EDS分析了颗粒的形态和元素组分对捕集机理的影响。结果表明:颗粒的物化特性与液滴对颗粒的捕集作用密切相关;燃油排放颗粒主要为球形含炭疏水颗粒;雾化液滴对其的捕集效率较低;添加润湿剂有利于提高液滴对燃油细颗粒的捕集效率,添加Silanol w22比用纯水液滴对颗粒的捕集效率提高了15%;不同润湿剂对捕集效率的促进作用差别较大。研究结果可以用于对不同润湿剂除尘效果进行测试和筛选。

The interaction of fine particles from oil combustion with water droplets was studied in a flow chamber experimentally. A novel fine particle capture technique with wetting agents was developed to investigate particle number concentration and size distribution before and after the interaction. The characteristics of particle capture with different wetting agents were also evaluated. The particle size distribution and concentration were measured by electrical low pressure impactor （ELPI）. The dependence of fine particles capture mechanism on microstructure and elemental compositions was analyzed with SEM and EDS. The results showed that the capture efficiency appeared to be closely related to the physico-chemical properties of fine particles. The SEM and EDS analysis showed that particles from oil combustion were basically spherical, carbon-containing hydrophobic particles. And the capture efficiency of fine particles with plain water droplets was low, but could be enhanced with wetting agents added to the atomized droplets. The capture efficiency could increase by 15% with adding Silanol w22 against plain water droplets. The investigation could be used to test and choose different wetting agents for fine particles capture.