超细颗粒物超声波团聚的影响因素

搭建了声波团聚模拟试验台架,选取中高声强的超声波作为声源,以燃烧产生的气溶胶模拟发动机的排气颗粒,利用扫描电迁移率颗粒物粒径谱仪测量了初始颗粒物参数以及团聚时间对声波团聚效率的影响.结果表明:该试验条件下,频率20kHz的声波对粒径10~487nm的颗粒具有团聚作用;声波作用时间延长,颗粒团聚效率提高,18s是该研究条件下比较理想的团聚时间;初始颗粒物浓度峰值对应的粒径越大,声波团聚效率越高,最高团聚效率能达到82.4%;初始颗粒数浓度越高,声波团聚效率越高,最高团聚效率在初始颗粒物峰值浓度粒径附近取得.

Influencing Factors of Acoustic Agglomeration of Ultrafine Particles

Abstract： A small scaled acoustic agglomeration test bench was built. Chosing the high intensity ultrasound as the sound source, selecting the aerosol with large amount of ultrafine particles which were produced by combustion as research objects, and using SMPS to measure the number of particles, the influence of initial particles parameters and the acoustic agglomeration periods on the agglomeration efficiency was studied. The results show that the acoustic wave of 20 kHz has some effect on the particles whose diameter range from 10 nm to 487 nm. Within the measuring range, a higher acoustic agglomeration efficiency can be obtained if the acoustic agglomeration acting period is longer. Besides, 18 seconds is an ideal duration under the test condition. If the initial particle diameter in peak concentrations is bigger, the acoustic agglomeration efficiency will be improved with a maximum of 82.4%.The acoustic agglomeration efficiency also has a positive correlation with initial particle concentration. The particles with a diameter in peak concentration often have a better agglomeration efficiency.