声波团聚技术是细颗粒物排放控制领域极具潜力的预处理方法。为提高团聚效率，提出了变频声波团聚的新方法。以热雾机产生的超细液滴气溶胶为研究对象，进行了定频与变频声波的团聚实验并比较两种条件下的团聚效率。此外，还实验研究了变频声波各种参数对团聚效率的影响。结果表明：在实验条件为10 W声功率、30 s团聚时间的情况下，6 kHz向1 kHz线性降低的变频声波处理30 s后，相对液滴含量较6 kHz定频声波条件下低8.12%，这表明变频声波符合液滴生长规律，对粒径不断变化的液滴团聚效率更高；当声功率较小时，提高声功率将使得团聚效率成比例地增加，直到相应的非线性声效应变得明显为止；较高的初始质量浓度意味着液滴间距更短，可显著提高声波引起的液滴间碰撞概率和团聚概率。

Acoustic agglomeration is regarded as a promising pretreatment to control the emission of fine particles.In order to improve agglomeration effect,a new method of constantlyvariablefrequency acoustic agglomeration was proposed.Taking the fine droplet aerosol produced by the aerosol generator as experimental object,the agglomeration experiments of acoustic waves with fixedfrequency and constantlyvariablefrequency were performed,and a comparative analysis of agglomeration efficiency under the two conditions was conducted.Besides,the influences of various parameters of constantlyvariablefrequency acoustic waves on agglomeration efficiency were investigated.The experimental results show that after the acoustic wave treatment of linear decrease from 6 kHz to 1 kHz,the relative droplet content with constantlydecreasingfrequency is 8.12% lower than that with fixedfrequency of 6 kHz,at acoustic power of 10 W and agglomeration time for 30 s.It indicates that the constantlyvariablefrequency acoustic wave is more effective on agglomeration of droplet aerosol whose diameters change constantly.The agglomeration efficiency increases proportionally with acoustic power at a low intensity,until the corresponding nonlinear acoustic effects become significant.The higher initial concentration means shorter separation distances among them,which will obviously improve the collision probability and agglomeration rate between droplets caused by acoustic waves.

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国家自然科学基金(51876197)；浙江省属高校基本科研业务费专项资金；浙江省新苗人才计划(2020R409045)；中国计量大学学生科技专项(2020YW44)；中国计量大学第二十三届学生科研计划(2020X23054)