【作者】 潘龙；

【导师】 薛平；

【作者基本信息】 北京化工大学 ， 机械设计及理论， 2012， 博士

【摘要】 由于开槽机筒单螺杆挤出机具有产量高、挤出稳定性好等优异性能，已经被越来越广泛地应用到塑料聚合物加工领域中。本研究中以螺旋沟槽单螺杆挤出机新型挤出理论研究为主线，对螺旋沟槽单螺杆挤出机固体输送段的固体输送机理、固体输送产量模型和不同固体输送机理下螺旋沟槽固体输送段的能耗等方面进行了探索和研究。在系统研究并结合理论分析基础上，研制了具有正位移输送能力的新型螺旋沟槽式单螺杆挤出机。该挤出机打破了单螺杆挤出机不能实现正位移输送的思想禁锢，在固体输送段实现了类似于异向双螺杆挤出机中的正位移输送方式，填补了国内外单螺杆挤出领域的一项技术空白。主要研究工作如下：1、通过将机筒衬套沟槽和螺杆螺槽视为对物料协同作用的整体系统，将嵌入机筒衬套沟槽和螺杆螺槽内的物料视为整体固体塞，建立了新型的弧板物理模型，通过对弧板固体塞的受力平衡和力矩平衡分析求解，建立了螺旋沟槽单螺杆挤出机固体输送段实现对整体固体塞正位移输送的边界条件方程，可以确定实现正位移输送条件下的机筒衬套沟槽和螺杆螺槽几何结构参数，实现了对固体输送段输送特性的可控。2、分析了螺槽中固体塞微元的受力情况，通过求解螺槽中固体塞微元的连续性方程和运动方程，得到了正位移输送机理下的固体输送段的建压方程式和固体塞运动速度方程式。在理论分析并结合实验验证的基础上，系统研究了不同机筒衬套沟槽和螺杆螺槽结构参数以及原料物性参数对正位移固体输送段压力分布的影响规律，揭示了正位移固体输送的建压机理。3、建立了新型的固体输送粒径模型，在粒径模型中，根据不同的机筒衬套沟槽深度和螺杆螺槽深度以及原料粒径之间的尺寸关系确立了固体塞内部不同位置处的剪切界面，使用正位移输送的边界条件方程讨论了不同的机筒衬套沟槽深度和螺杆螺槽深度以及不同的原料粒径对剪切界面上的固体输送机理的影响规律，利用不同结构参数的机筒衬套和螺杆装置以及不同的原料粒径进行了实验验证，并确立了不同固体输送机理下螺旋沟槽固体输送段的产量和能耗计算模型。4、通过系统分析和理论研究，研制了具有正位移固体输送能力的新型螺旋沟槽单螺杆挤出机，并在该挤出机实验平台基础上，自行研制了螺杆挤出固体输送段在线模拟试验机，用于在线真实检测固体输送段末端的压力值和固体输送段的产量和能耗等参数。本研究取得的阶段性成果不仅可为螺旋沟槽正位移输送单螺杆挤出机的工业化应用提供理论指导，还可为我国高分子材料科学与技术的进步提供新的设备平台。更多还原

【Abstract】 Grooved barrel single screw extruders were widely used to processplastics for molding because higher throughput and better pressure invariancewere revealed than before during extrusion. Based on the study of the novelextrusion theory in helically grooved single screw extruders, the solidsconveying mechanism, throughput model and energy consumption was deeplyresearched and detailed in this paper. By the systematic research andtheoretical analysis, the novel helically grooved single screw extruder withpositive conveying was first designed and manufactured. In the novel extruder,not the friction-drag conveying mechanism but the positive conveyingmechanism similar to that in the counter-rotating twin-screw extruder wasachieved, which made up for the technology blank of the single screwextrusion. The main research efforts are summarized as follows:1. In the theory, screw channel rotated against static grooves, whichbehaved as the cooperative twin-screws. They turned as two parallel arc plates,between which an arc-plate solid-plug composed of the solids embedded in thegroove and screw channel was assumed. By analyzing the forces and torque on the solid-plug, the boundary condition equations for positive conveyingwere built and used to guide the reasonable designs of the groove and screwgeometry to positively convey the solid-plug in the helically grooved feedzone, which achieved the effective control for solids conveying characteristics.2. After analyzing the forces on the solid-plug, the continuity equationand kinematic equation was resolved to obtain the pressure equation in thesolids conveying zone and the conveying velocity equation of the solid-plug inthe positive conveying mechanism. In addition, the effects of the groove andscrew geometry and the friction coefficients on the characteristics of thepressure distribution in the solids conveying zone were theoreticallyresearched and well verified with the experimental data. Based on these, thepressure-building mechanism with positive conveying was accurately revealedto achieve steady extrusion.3. A novel particle-size conveying model was proposed by the differentdimension relationships of the groove depth, screw channel depth and particlesize in the helically grooved feed section. In the model, shear interfaces insidethe solid-plug were determined and the effects of the different differentdimension relationships on the solids conveying mechanism on the shearinterfaces were discussed by the boundary condition equations for positiveconveying. After the theoretical analysis being examined by the measured data,the calculating models for the throughput and energy consumption of thesolids conveying zone were established with different solids conveying mechanisms.4. By the systematic analysis and theoretical research, the novel helicallygrooved single screw extruder with positive conveying was invented. On thebasis of the novel extruder, a specially designed instrument, called onlinetesting instrument of solids conveying zone for single screw extrusion, wassuccessfully developed to online measure the pressure, throughput and energyconsumption of the solids conveying zone.Generally speaking, all the preliminary research achievements canprovide not only the theoretical guideline for industrial application but also ascientific research stage for the improvement of the polymer materials scienceand technology of China.更多还原