离心式挤出机结构创新与固体输送及增压机理的研究

【作者】 赵晶；

【导师】 吴大鸣；

【作者基本信息】 北京化工大学 ， 化工过程机械， 2008， 博士

【摘要】 离心式挤出机是一种新型聚合物加工机械,其主要创新点为将离心力场应用于固体输送及增压。本文以离心式挤出机的工作机理为主线,对离心式挤出机结构设计、工艺参数、固体输送增压机理、固体输送压力分布状态的数值模拟、固体输送增压机理的实验验证等多个方面进行探索和研究。本文全面地剖析了离心式挤出机的输送增压、圆盘熔融、计量挤出工作机理,提出了离心式挤出机的总体设计。并详细讨论了离心式挤出机的主要结构,其中包括主机、传动系统、控制测量系统、加热冷却系统、以及密封结构。同时,本文也阐述了离心式挤出机主要工艺参数以及结构参数的设计,其中包括离心力场、工作转速、剪切速率、传热能力、密封能力以及圆盘熔融段法向应力等。另外,由于离心式挤出机属于高速旋转机械,本文对其临界转速也进行了有限元数值分析。除上述离心式挤出机设计问题外,本文着重研究了离心式挤出机聚合物输送增压机理,建立了在离心力场的作用下聚合物输送压力分布的数值模型,得到转鼓中聚合物输送压力分布方程;同时,利用固体输送压力分布方程,分析了转鼓结构几何参数、聚合物物料属性、转鼓材料以及操作工艺条件对转鼓中聚合物输送压力分布的影响。数值分析研究表明,选取适当的转鼓锥角α、半径R_n以及转鼓材料,同时针对不同聚合物,选择不同的转速n可以得到预期的固体输送压力;提高转鼓内壁的表面光洁度、对转鼓内壁进行表面涂层处理,可大大减少摩擦,可将原本浪费的摩擦上的能量用以提高聚合物固送压力。根据离心式挤出机的聚合物输送机理,设计出聚合物输送增压实验装置,用以对离心式挤出机输送压力数值分析结果进行实验验证。实验测试结果表明,实验数据与数值分析数值吻合较好,证明了离心式挤出机固体输送压力分布数学模型具有合理性以及预测性。离心式挤出机将离心力场引入到聚合物加工领域,本研究取得的阶段性成果不仪可为该机的开发和应用提供理论依据,而且会对其它相关领域的聚合物加工技术与理论的研究产生辐射作用。更多还原

【Abstract】 Centrifugal extruder is a new type of polymer processing machine, used centrifugal force field in polymer processing. In this paper, four aspects of the equipment--- the innovation technology of centrifugal extruder, solid conveying mechanism, mathematical simulate of the distribution of solid conveying pressure and experiments are studied for the development of centrifugal extruder.It is introduced comprehensively that solid conveying, melting, mix and metering of centrifugal extruder. The innovation technology of centrifugal extruder is introduced, including main machinery, drive system, control and measuring system, heating-cooling system and seal system. And the paper lists the parameters of main operation and machinery on centrifugal extruder. There are centrifugal field, rotate speed, power, shear rate, normal stress difference in disk stage seal capability and heating transfer. Because the centrifugal extruder is a kind of the rotation equipment with high speed, the analysis of vibration is made by ANSYS software.Polymer solid conveying processing of centrifugal extruder is studied. Built mathematical simulation modal of the conveying pressure distribution, the equation expressed the conveying pressure distribution can be obtained. Otherwise, the effects of pressure distribution, including rotor drum, polymer physical properties and operational conditions on the conveying pressure distribution have been analyzed.By studied, the conclusions are gotten that by reasonable rotor drum and rotation speed, the centrifugal extruder can established the necessary solid conveying pressure; the main geometrical parameters of the rotor drum influencing on the solid conveying pressure are the diameter and slope angle of rotor drum; the friction factors between the polymer and the wall of the rotor drum or dish can influence on the solid conveying pressure distribution; the physical properties of polymer influencing on the solid conveying pressure distribution are the density and friction factor of the polymer.The equipment is designed for validating the mathematical model for calculation of the solid conveying pressure. The results of the experiments show a good coincidence with the theoretical predicts.All the preliminary investigations can provide theoretical basis for application and development of this type of polymer processing machine.更多还原