啮合同向差速双螺杆挤出机挤出聚乳酸流场分析

目的：探究不同差速比的螺杆组在流道性能上的差异，明确差速对聚乳酸材料挤出性能的影响。方法：应用Solidworks软件建立4组差速双螺杆组，通过Fluent软件进行网格划分和有限元数值模拟，使用CFD-post软件分析计算结果，并对其性能进行验证。结果：当进出口压力分别为0.2，0.5 MPa，单头基准转速为30 r/min时，差速比为1∶2和1∶3的螺杆在不同性能下各有优劣，螺杆的产量和机筒内压力在差速比为1∶2时具有优势，螺杆的混合能力在差速比为1∶3时具有优势。结论：对比传统双螺杆挤出机，差速双螺杆挤出机对聚乳酸材料的挤出性能为正向影响，可作为全新的聚乳酸改性设备。

Analysis of the flow field in a meshing and co-rotating differential twin screw extruder for extruding polylactic acid

Objective: To explore the differences in runner performance of screw groups with different differential ratios, and to clarify the effects of differential speed on the extrusion performance of polylactic acid materials. Methods: Four groups of differential twin screw groups were established by Solidworks software, meshing and finite element numerical simulation were carried out by Fluent software, the calculation results were analyzed by CFD-post software, and the contours and discounted plots of various characterization parameters were combined, and they were verified by experiments. Results: Under the condition that the inlet and outlet pressures were 0.2 MPa and 0.5 MPa, and the reference speed of a single head was 30 r/min, the screws with a differential ratio of 1∶2 and 1∶3 had their own advantages and disadvantages under different properties, and the screws with a difference ratio of 1∶2 for output and pressure in the barrel had an advantage. In terms of mixing capacity, a screw with a differential ratio of 1∶3 had an advantage. Conclusion: Compared with the traditional twin-screw extruder, the differential twin-screw extruder has a positive impact on the extrusion performance of polylactic acid materials, and can be used as a new polylactic acid production equipment.