共查询到20条相似文献,搜索用时 93 毫秒
1.
应用多普勒激光测速法测量同向旋转双螺杆挤出机捏合区域的速度分布。在90r/min分的转速下,测量两螺杆捏合区中推力区和阻力区的轴向速度和法向速度。 相似文献
2.
3.
同向啮合双螺杆挤出机捏合块流道三维流场分析 总被引:9,自引:0,他引:9
利用ANSYS有限元分析软件对啮合同向双螺杆挤出机的捏合块流场部分进行了三维模拟分析。通过速度场求出流量 ,并求出拉伸速率、剪切速率及剪切应力来衡量混合效果。得到了机筒表面和啮合区的压力分布 ,找出了捏合盘几何条件 (间隙、错列角 )及操作条件 (转速、压差等 )对挤出机混合效果的影响。 相似文献
4.
用同向旋转双螺杆挤出机研究了E-SBR/白炭黑/硅烷橡胶/填料复合材料(RFC)的连续混炼工艺.研究了混炼区捏合块类型不同的3种螺杆配置:正向捏合系统、中位捏合系统和反向捏合系统,对比了3种螺杆配置的混炼效果.研究了胶料的性能,如填料-填料相互作用、门尼黏度以及硫化胶的力学性能.结果发现,与中位和正向捏合系统相比,采用... 相似文献
5.
本文对双螺杆挤出机设计中进料口的形状和位置,螺纹截面形状,螺纹截面形状,捏合块外形,捏合区外部条件及排列方式等设计问题作了探讨。 相似文献
6.
7.
利用不同螺杆组合的双螺杆挤出机制备了超细碳酸钙填充聚丙烯试样,通过测量挤出机的功率来计算其能耗,并测试了试样的拉伸性能,研究了45°捏合盘厚度、塑化段捏合盘错列角、转子类螺纹元件位置及多组捏合盘连续排列形式对挤出机能耗和试样拉伸性能的影响。结果表明,45°捏合盘厚度为30 mm或45 mm、塑化段捏合盘错列角为30°或45°、转子类元件放在塑化混合段之后,均可在保持试样较高拉伸强度的条件下有效地降低挤出机能耗。多组捏合盘连续排列方式下的挤出机能耗并未大幅增加,可适用于需要高剪切物料的挤出生产。 相似文献
8.
采用同向啮合双螺杆挤出机的不同螺杆组合形式,研究了捏合错列角对双螺杆挤出聚合物共混物表层和内层分散相粒子粒径及其分布的影响。发现螺杆后段采用不同错列角的捏合盘,对于分散相粒子尺寸和分布状态都有明显影响。在塑化区多段式组合的后段采用剪切强、停留时间长的捏合盘(K45°、K60°),可有效地减小分散相粒子尺寸但分布状态不理想;使用 K30°的捏合盘时,分散相粒子分布状态最佳;整体两段式螺杆的前段混合段中设置 K45°捏合盘,有利于分散相含量较少情况下粒子的尺寸及分布的均匀性的提高。 相似文献
9.
本文作者建立了一种描述在同向旋转啮合型双螺杆挤出机中广泛应用的捏合盘元件的熔体输送特性及混合特性的三维、等温、幂律流动理论模型,并利用流体有限元方法及大型计算机程序对流场进行数值求解,得出了流场的速度分布,压力分布及剪应力分布。这些结果较全面地反映了捏合盘的几何尺寸、物料特性和运转条件之间的关系,得出了许多前人所建立的模型不曾得出的结论,这对认识捏合盘的工作机理、指导捏合盘设计和选择挤出工艺有一定指导意义。 相似文献
10.
11.
Local residence time and distributive mixing were measured in conveying sections and kneading blocks of a twin screw‐extruder. The residence time measurements were completed using carbon black as the tracer and an infrared temperature probe to detect the temperature decrease caused by the changing surface emissivity. The validity of this experimental technique was extensively evaluated. A mixing limited interfacial reaction between polymer tracers was used to directly measure the distributive mixing in the twin‐screw extruder. Possible relationships between mixing and residence time in the sections of the twin‐screw extruder were investigated by combining these two measurements. Distributive mixing in conveying sections was related to the local average residence time and the fill. In contrast, distributive mixing in kneading blocks was related to the local average number of screw revolutions experienced by the polymer. Forward stagger kneading discs achieved the greatest amount of distributive mixing, which was attributed to a combination of local stagnant flow regions and more frequent interfacial reorientation. 相似文献
12.
13.
啮合同向双螺杆挤出过程轴向循环流道三维流场分析—轴向循环流场分析(Ⅱ) 总被引:5,自引:2,他引:3
介绍了作者在啮合同向双螺杆某一轴向位置设置一非啮合段(且该段其中一根螺杆是反向螺纹元件),从而将轴向循环流动的概念引入到啮合同向双螺杆挤出过程中,并利用ANSYS有限元分析软件对啮合同向双螺杆挤出过程轴向循环流道中的非牛顿流体等温流动进行了三维模拟分析。在得出速度场和压力场的基础上,还对剪切速率、剪切应力及剪切粘度进行了模拟,并将各模拟结果与未引入轴向循环流的啮合同双螺杆挤出过程常规螺纹元件流道的模拟结果进行了比较。 相似文献
14.
15.
挤出机螺杆元件材料及工艺分析 总被引:4,自引:0,他引:4
为满足塑料填充、增强和共混改性的要求 ,对同向旋转双螺杆挤出机的典型螺杆元件螺纹套、捏合块的不同材料及制造工艺进行了分析和比较。主要介绍了 3 8CrMoALA合金钢调质氮化处理 ;高速钢 (W 6Mo5G4V2 、W 18Cr4V)整体淬火 ;40Cr调质基材涂层工艺。 相似文献
16.
The objective of this work is to validate, via comparison with available experimental data, the results obtained from the numerical simulation of polymer melt flow in the kneading disc section of an intermeshing co‐rotating twin screw extruder. A quasi‐steady state 3‐D solution of the conservation equations via the finite element method was obtained, and comparisons were made with experimental pressure profiles measured by McCullough and Hilton (1) on various kneading block elements. These measurements helped provide understanding of the flow patterns developed within the unit and provided a comprehensive approach of validating the numerical model. Results confirm the importance of a fully 3‐D model for this type of geometry, where the model predicts the development of flow patterns in the radial directions and within the intermeshing region. The influence of inlet and outlet boundary conditions was studied and it was determined that they play an important role in the physical significance of the model solution. Comparisons of the simulation results with experimental data by McCullough and Hilton (1) for two different configurations of kneading discs showed good agreement, with some differences in the peaks of pressure produced at the narrow clearances encountered in intermeshing co‐rotating twin screw extruders. Differences between simulation and experiments are attributed to a number of factors. It is difficult to measure the very steep pressure gradients generated over small lengths. The assumptions of isothermal flow and quasi‐steady state may cause an over‐prediction of the pressure peaks. Simulation results describe the general trends and produce good quantitative agreement in most of the kneading disc region. 相似文献
17.
设计了自洁型非对称同向双螺杆,并采用实验研究及数值模拟方法分析其混合特性。采用活性纳米CaCO3(nano CaCO3)填充线形低密度聚乙烯(PE LLD)的体系进行实验研究,在挤出量一定的前提下分别在自洁型非对称同向双螺杆挤出机以及普通同向双螺杆挤出机上造粒,通过扫描电子显微镜观察产品中nano CaCO3分布情况。结果表明,非对称双螺杆挤出PE LLD/nano CaCO3复合材料中nano CaCO3分布较为均匀,粒径尺寸更小,具有明显的增韧效果,这与数值模拟结果一致。 相似文献
18.
19.
Shaffiq A. Jaffer Victor L. Bravo Philip E. Wood Andrew N. Hrymak Joseph D. Wright 《Polymer Engineering and Science》2000,40(4):892-901
A comparison of the results of a 3D model for the simulation of flow in the kneading disc region of a fully intermeshing twin screw extruder has been done against particle image velocimetry (PIV) experimental data. Experimental results using a geometry with an extended first and last kneading disc to capture the simplified inlet and outlet boundary conditions, are in good qualitative agreement for low flow rates. The results showed good agreement at flow rates less than 5 mL/s and rotation speeds of 60 rpm, while above that there was poor agreement. These results highlight the importance of the use of appropriate boundary conditions for the accurate prediction of the flow field. The flow field within the kneading discs with forward conveying elements placed before and after the kneading discs was also measured. For a flow rate of 8.5 mL/s and 60 rpm, results showed good agreement when conveying elements were deployed before and after the kneading blocks whereas for lower flow rates there was poor agreement. 相似文献
20.
A model for flow start‐up of a Newtonian liquid in an initially empty modular selfwiping co‐rotating twin screw extruder is developed. The changes of length of fill in front of the die and kneading disc block elements and output flow rate with time were predicted for various modular screw configurations. Experiments were also carried out on a laboratory modular machine with windows to verify predictions. Generally, good agreement with the flow analysis was found. 相似文献