The Theoretical And Experimental Study On Acoustic Agglomeration Of Fine Particles

Nowadays, the fine particles suspending is the major pollution in urban areas of our country. The technology of acoustic agglomeration is considered as the most promising and effective pre-treat method to remove these particles. Though the history of research on acoustic agglomeration mechanisms could date from the beginning of the 20 th century, the contributions of different mechanisms on acoustic agglomeration is controversial and the application on industry still has some problems and bottlenecks. Based on the reasons above, the manuscript works on the mechanisms of acoustic agglomeration of fine particles theoretically and aspects of key-technology on designing the system to eliminate these fine particles efficiently.The theoretical part of manuscript researches on the classical agglomeration mechanism of the orthokinetic interaction; introduces the agglomeration mechanism of mutual radiation, acoustic wake effect, gravity sedimentation and Brownian motion agglomeration; combined the concept of the reflection method, the paper establishes the theoretical model which three particles along a line with the direction of acoustic wave, analyzes the hydrodynamic interactions between particles and gets the acoustic agglomeration frequency function(called kernel function in short). The experimental part of the manuscript analyzes the acoustic information of agglomeration cabin; designs, assembles the system of acoustic agglomeration; and the manuscript works on the effect of the main key parameters(like frequency, SPL, operation time) on the efficiency of agglomeration.The results have shown that the mechanism of acoustic agglomeration combined the reflection method can explain the agglomeration of the monodisperse fine aerosol particles and the gravity sedimentation of these particles. The efficiency of acoustic agglomeration is very sensitive to the acoustic frequency, and there is an optical frequency which can get the efficiency of agglomeration maximization; the efficiency increases with the SPL; the longer operation time can make the efficiency of the acoustic agglomeration of fine particles bigger.