【作者】 王奎； 刘雪晴； 鲁录义；

【Author】 Wangkui;Liu Xueqing;Lu Luyi;School of Energy and Power Engineering,Huazhong University of Science and Technology;

【机构】 华中科技大学能源与动力工程学院；

【摘要】 以空气和煤粉颗粒为工质,建立撞击流反应器,采用CFD-DEM模型模拟反应器中空气和颗粒运动行为,从而得到撞击流流场及颗粒运动轨迹。根据所选取的颗粒软球接触模型及流场曳力模型,通过FLUENT中用户自定义函数(UDF)编写并扩展完善颗粒在撞击流流场中碰撞的DEM程序,研究了不同气流入口速度比下非对称撞击流中颗粒的运动形态,讨论了在不同进口速度比下撞击流流场中颗粒的停留时间变化规律。模拟结果表明UDF能将颗粒的材料、恢复系数、粒径等属性以及计算的时间步长都完整考虑进来,保证颗粒能较好的与流场进行耦合,且非对称撞击流能增加颗粒渗入反向气流的概率,有效提高颗粒在撞击活性区域的平均停留时间。更多还原

【Abstract】 An impinging stream reactor is constructed by using air and pulverized coal particles as working fluid.The CFD-DEM model is applied to simulate the motion of air and particles in the reactor,and then the flow field of the impinging stream and particle tracking were obtained.According to the soft sphere contact model and drag force model,the DEM program of particle collision in the impinging stream field is written and extended by adopting the user-defined function(UDF) in FLUENT.The motion patterns of particles in the asymmetric impinging stream at different inlet velocity ratios were investigated,and the residence time variation of particles in impinging stream flow at different inlet velocity ratios is discussed.The simulation results show that the particle material,recovery coefficient,particle size,and the time step of the calculation,all these influences,can be fully taken into account by using UDF,this makes that the particles can be well coupled with the flow field.Additionally,the asymmetric impinging stream can increase the probability of particles penetrating into the reverse flow,and effectively increase the average residence time of particles in the impinging active region.更多还原