啮合块错列角对三螺杆混合段混合效率的影响

采用有限元法和网格重叠技术,利用Carreau-Bird流体模型,对同向啮合三螺杆挤出机混合段进行了三维混合数值模拟。计算了三螺杆挤出机的最大剪切速率、混合指数以及瞬时和平均时间混合效率等参数,并与双螺杆挤出机进行了对比分析。结果表明,在相同工况下,三螺杆挤出机的瞬时和平均时间混合效率大于双螺杆挤出机。

Effect of Stagger Angles of Mixing Sections on the Mixing Efficiency in Intermeshing Tri-Screw Extruders

Three dimensional mixing characteristics of the kneading elements in a intermeshing co-rotating tri-screw extruders were simulated. The mesh superposition technique （MST） and the Carreau-Bird flow model were employed in this simulation. The mixing mechanisms in the kneading elements were analyzed with the mixing evaluation parameters, such as maximal shear rate, mixing index, instantaneous and time averaged efficiencies, which were compared with those in the twin screw extruders. The results show that, in the same operating conditions, the maximal shear rate, mixing index, instantaneous and time averaged efficiencies of the tri-screw extruders are bigger than those of the twin screw extruder. It shows that the tri-screw extruder has better mixing efficiency than the twin screw extruder.