声波与喷雾对于飞灰颗粒团聚的影响

Influence of acoustic wave and water spray on the agglomeration of fly ash particles

为了研究声波团聚的影响因素,以燃煤飞灰细颗粒作为声波团聚的实验对象,使用光学颗粒物粒径谱仪测量颗粒的粒径分布与浓度,主要研究了声波频率与喷雾对声波团聚的影响。结果表明:在声波的作用下,细颗粒浓度显著减少,且声波团聚效果对频率较为敏感;无论在高声压还是低声压级下,1400Hz的频率下能获得最佳的团聚效果;在加入喷雾后,颗粒物浓度显著减小,且随着喷雾量增大,颗粒物浓度越小;分析了喷雾增强团聚效果的机理:在加入喷雾后,细颗粒间的相对运动增强;同时喷雾颗粒增大了颗粒浓度,增大了细颗粒碰撞概率;此外,喷雾改变燃煤飞灰细颗粒的表面特性,使颗粒的表面黏性增大,有助于团聚体形成。

In order to study the influencing factors of sound wave agglomeration, an aerosol formed by mixing coal-fired fly ash with air was used as an experimental object, and the particle size distribution and concentration of the particles were measured by an optical particle size spectrometer. The experiment mainly studied the effects of sound frequency and water spray on acoustic agglomeration. The result showed:under sound waves, the concentration of fine particles was significantly reduced, and the effect of sound agglomeration was sensitive to frequency;at high or low sound pressure level(SPL), we got the best agglomeration effect at 1400 Hz;after the addition of spray, the concentration of the particles was significantly reduced, and as the amount of spray increased, the concentration of the particles became smaller. The mechanism of spray enhancing agglomeration effect was analyzed: the addition of spray enhanced relative motion between fine particles;spray particles increased particle concentration and the chance of fine particle collision;the spray changed the surface characteristics of the fine particles of coal-fired fly ash, which increased the surface viscosity of the particles and contributed to the formation of agglomerates.