棱顶间隙对4WS密炼机流体混合特性影响

Effects of Different Clearance on the Mixing Characteristics in the 4WS Internal Mixer

四翼转子(4WS)密炼机是新型转子密炼机,具有较小的螺旋角和较大扫掠范围的长棱,吃料迅速,短时间内达到较好的混合效果等优点。利用Polyflow有限元软件,对不同结构4WS密炼机进行三维瞬态流场分析。分析转子与转子及转子与外壁间隙的变化对流场混合效果的影响,重点分析特殊几何截面的剪切速率,不同位置点的李雅普诺夫指数、瞬时混合效率、平均混合效率、分离尺度、对数拉伸。分析结果表明,在一定范围内,随着转子间隙的减小,4WS密炼机混合性能逐渐提高。

Internal batch mixier with 4WS（four wing） rotor is the novel mixing equipment, which has some advantages to achieve better mixing efficiency in short time, such as small helical angle, wide sweep range and quick feed. Finite element method was adopted to calculate the three dimensional transient velocity distribution of the 4WS rotor internal mixer. The effects of gap between rotor and barrel on the mixing efficiency were analyzed by means of shear rate, Lyapunov Exponent, instantaneous mixing efficiency, time averaged mixing efficiency, segregation scale and logarithm of stretching. The results show that the smallest rotor clearance has the better mixing performance within limits.