颗粒尺度、形状对机械搅拌扭矩、功率影响的数值模拟

Numerical simulation of effects of particle size and shape characteristics on mechanical stirring torque and power

采用离散单元法数值模拟方法,研究机械式粉体混合机工作过程中搅拌功率、扭矩的变化规律;选用桨叶直径为160 mm的机械式粉体混合机,数值模拟转速对扭矩、功率影响,验证数值模拟的准确性;模拟研究颗粒尺度、形状和分布对搅拌功率、扭矩的影响。结果表明:在颗粒充填体积分数为35%、搅拌转速分别为100、200、300、400、500 r/min的条件下,搅拌扭矩、功率均随颗粒平均粒径的减小而增大;对于任意粒径的颗粒,搅拌功率均随转速增大呈线性增大,搅拌功率变化的幅度随粒径减小而增大;同一粒径尺度下,颗粒的分布对搅拌扭矩影响较小;在填料高度相同条件下,搅拌功率、扭矩随颗粒球形度的减小呈降低的趋势;对于外形接近或形状相同的颗粒,搅拌扭矩随球形度的减小呈降低的趋势。

Discrete element method was used to simulate the variation of mixing power and torque in working process of mechanical powder mixer.Using a mechanical powder mixer with a blade diameter of 160 mm,the numerical simulation of the influence of rotating speed on torque and power was carried out to verify the accuracy of the numerical simulation.The effects of particle size,particle shape and particle distribution on stirring power and torque were simulated.The results show that when the particle filling amount is 35%and the stirring speed is 100,200,300,400 and 500 r/min,the stirring torque and power increase with the decreasing of average particle size.For particles with any particle size,the stirring power increases linearly with the increasing of rotating speed,and the variation of stirring power increases with the decreasing of particle size.Under the same particle size scale,the type of particles has little effect on the stirring torque and under the same packing height,the stirring power and torque decrease with the decreasing of sphericity.For particles with similar shape or the same shape,the stirring torque decrease with the decreasing of sphericity.