Radial mixing and segregation of granular bed bi-dispersed both in particle size and density within horizontal rotating drum

“S+D”型二元颗粒床在水平转筒内的径向混合与分离（英文）

Taking simultaneous variations in both particle volume and density into account, the radial mixing and segregation of binary granular bed in a rotating drum half loaded were investigated by a 3D discrete element method. Then, based on the competition theory of condensation and percolation, radial segregation due to differences in particle volume and/or density was analyzed. The results show that if either percolation effect induced by volume difference or condensation effect induced by density difference dominates in the active layer of moving bed, separation will occur. Controlling the volume ratio or density ratio of the two types of particles can achieve an equilibrium state between percolation and condensation, and then homogenous mixture can be obtained. When the percolation balances with the condensation, the relationship between volume ratioand density ratiopresents nearly a power function. Scaling up a rotating drum will not affect the mixing degree of the granular bed so long as the volume ratio and density ratio are predefined.

同时考虑颗粒体积差异和密度差异,采用三维离散单元法模拟填充率为50%时水平转筒内二元颗粒床的径向混合与分离过程。结合渗流与凝聚竞争机理,对密度差和体积差导致的颗粒床分离现象进行分析。结果表明:颗粒体积差引起的渗流机理或密度差引起的凝聚机理均会作用于颗粒床的活动层,导致颗粒分离;调整颗粒体积比和密度比可使渗流和凝聚机理相互平衡,实现物料在转筒内的均匀混合;当渗流与凝聚平衡时,颗粒的体积比与密度比基本呈幂函数关系;当颗粒体积比和密度比确定后,二元颗粒床的混合度不受转筒尺寸的影响。