This paper studies the acoustic agglomeration of fine particles of the coal fly ash in the acoustic field agglomeration device, based on the coupling population balance model (PBM) for acoustic agglomeration of fine particles and the modified kinetic theory of the fine particle flow. The new root mean square of the agglomeration kernel function operates according to the acoustic agglomeration mechanism. We present the theoretical investigation of the problem and then compare it with experimental results. The results show that the agglomeration process of particles in different size ranges is dominated by different agglomeration mechanisms. Moreover, we show the numerical simulation of the acoustic agglomeration process of the particles using the new agglomeration kernel function, which is consistent with the experimental results. In addition, the particle flow in the acoustic field agglomeration device presents a typical turbulent structure, and a large particle agglomeration occurs near the wall and outlet. (C) 2019 Elsevier B.V. All rights reserved.