燃煤可吸入颗粒物声波团聚效果的实验研究和数值分析

1引言我国是燃煤大国,每年燃煤产生的一次和二次颗粒物数量巨大。排放到空气中的颗粒物不仅降低了大气的能见度,影响环境和气候,而且危害人体健康,使致病率和死亡率上升。可吸入颗粒物(<10μm)是目前我国城市大气环境的主要污染物,尤其是空气动力学直径小于2.5μm的颗粒物(PM2.

Experimental Study and Numerical Analysis of the Acoustic Agglomeration Effectiveness of Inhalable Particles of Burned Coal

Through a theoretical analysis of a plane standing-wave sonic field a test rig on acoustic agglomeration and removal characteristics of burned coal inhalable particles has been designed and set up.Under the condition of the inhalable particles of burned coal being subject to the action of a high intensity sonic field studied was the impact of different acoustic intensity and particle retention time in sonic field on the change of particle diameter distribution prior to and after the acoustic agglomeration.On the basis of experiments a numerical calculation was conducted.A comparison of the results of numerical calculation with those of experiments revealed a relatively good agreement.Moreover,by way of a numerical algorithm a forecast was performed of the influence of particle initial concentration and acoustic frequency.The results of experiments and numerical calculation indicate that as for the inhalable particles an increase in acoustic intensity,a lengthening of retention time in sonic fields and an enhancement in initial particle concentration is,without exception,favorable to particle agglomeration.It has been found that an increase in frequency can contribute to the agglomeration of small particles.However,there exists an optimum frequency for attaining integral removal effectiveness.