三螺杆挤出机固体输送理论的实验解答.doc

三螺杆挤出机固体输送理论的实验研究* 何和智，赵耀，董国庆，石保虎 (华南理工大学聚合物新型成型装备国家工程研究中心聚合物成型加工工程教育部重点实验室，广东 广州510641 摘要: 关键词: Research on Solid Conveying Theory of Tri-screw Extruder HE He-zhi ZHAO Yao DONG Guo-qing SHI Bao-hu （）Abstract: In this paper, the intermeshing region was studied first and throughput was obtained. Then physical model of non-plug solid conveying in the non-intermeshing region was established and mathematical model was obtained by the use of virtual work principle. Solid conveying?efficiency in the non-intermeshing region was obtained via solving three-layer model of non-plug solid conveying and getting average velocity of material. By introducing transformation coefficient, the intermeshing region was turned into non-intermeshing region, thus solid conveying in the intermeshing region and non-intermeshing region was integrated into non-plug solid conveying, equivalent?screw channel fill ratio and solid conveying?efficiency were obtained. Solid conveying of tri-screw extruder was consist of these. Some experiments were done with particulate material (LDPE) and?powder material (PP) in order to verify solid conveying theory established and study the influencing factors of solid conveying. Key words: Tri-screw extruder; Solid conveying theory; Positive displacement conveying; Non-plug flow; Throughput 三螺杆挤出机塑化、熔融、混合的能力优异，尤其适合于多相多体系物料的共混改性和挤出成型。同时，啮合区的增加使得螺杆的碾压剪切面积成倍增加，因而可对物料形成更为高效的剪切、挤压、揉捏作用[1]。经典的固体输送理论是达涅耳(Darnell)和莫耳(Mol)提出的Darnell-Mol理论，该理论是以固体对固体摩擦的静力平衡为基础，将固体输送段中的物料看成是密实的无内形变的固体塞。Tadmor等[2,3,4]对经典的固体输送理论作了进一步的完善，并考虑了物料密度和螺槽深度对固体输送的影响。Darnell-Mol理论和TedderChung[5]则认为固体床周围的熔体产生的粘性牵附力决定了固体输送的性能。房士增等[6]提出了非塞流固体输送理论。朱复华等[7,8]进一步提出单螺杆挤出的非塞流固体输送理论，该理论是将螺槽中未压实的物料看成散粒体，建立了非塞流固体输送理论的物理模型和数学模型。江顺亮等[9,10,11]提出了单螺杆挤出的非塞流固体输送三层模型，该模型将螺槽中的物料沿着螺槽深度方向划分为三层，认为每一层物料是一个固体塞，并得到了产量与压力降的三次方程。刘春晖[12]对纯UHMWPE树脂粉末在单螺杆挤出机加料段的压力建立进行了研究，建立了非塞流固体输送的n层模型, 刘廷华[13]采用全程透明视窗双螺杆挤出机，进行动态可视化挤出实验研究，将非塞流固体输送理论应用于啮合同向双螺杆挤出机，提出了啮合同向双螺杆挤出中非啮合区的固体输送理论模型。 固体输送是挤出过程的重要组成部分，研究固体输送的目的在于研究影响固体输送的因素，找到提高固体输送效率的方法