Abstract: Based on integral modeling method，FLUENT software was used to simulate fluidized bed jet mill to explore the changes in internal flow field under different actuating medium. Simulation results showed that there is little difference in air flow velocity pressure with different actuating medium，while a higher outlet velocity can be obtained when actuating medium with lower molecular weight flow through the Laval nozzle. Meanwhile，higher velocity of injective air in grinding chamber provides more chance for particles to enter the axial velocity area. Therefore，an actuating medium with lower molecular weight can increase the grinding efficiency effectively. Simulation results for different inlet pressure and back pressure on grinding airflow showed that the airflow velocity increases obviously with the building up in the inlet pressure，but less effected by the building up in the back pressure .

摘要： 为研究流化床气流粉碎机在不同工质下内部流场的变化，利用FLUENT流体计算软件对流化床气流粉碎分级机进行整体建模。对不同工质的模拟结果表明：不同工质下气流动压相差不大，但分子量越小的工质经过Laval喷嘴得到的喷嘴出口速率越大，同时粉碎腔内的引射气流速率越大，颗粒进入轴心速率区的概率也增大，故分子量小的工质能有效提高粉碎效率。不同进口压力和背压对气流速率影响的模拟结果表明，提高进口压力，气流速率明显提高；增大负压对提高气流速率不明显。