共查询到17条相似文献,搜索用时 437 毫秒
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在分析机筒衬套沟槽槽深、螺杆螺槽槽深和加工物料粒径关系的基础上,建立了沟槽机筒单螺杆挤出机3种常见的固体输送段产量粒径模型,该模型可用于研究机筒衬套沟槽槽深、螺杆螺槽槽深和颗粒物料粒径对固体输送机理的影响并定量计算沟槽机筒单螺杆挤出机固体输送段产量。此外,通过不同的机筒和螺杆组合及不同粒径的原料在自制的在线模拟试验机上对该模型进行了验证和试验分析。 相似文献
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螺旋沟槽单螺杆挤出机双螺棱推动理论模型的研究 总被引:2,自引:0,他引:2
潘龙;贾明印;薛平;金志明;唐广利 《中国塑料》2010,24(11):94-99
通过在单螺杆挤出机固体输送段机筒内壁开设螺旋沟槽,建立了将机筒与螺杆视为一个对物料协同作用的整体的新型物理模型——弧板模型;同时将嵌入机筒沟槽与螺杆螺槽中的物料视为固体塞,提出了新型"双螺棱推动理论",弥补了单螺杆挤出机不能实现正位移输送的传统理论缺陷;最后,通过理论分析确定了螺旋沟槽挤出机由摩擦拖曳输送向正位移输送转换的边界条件方程及正位移输送下沟槽结构参数的设计准则。 相似文献
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Janusz W. Sikora 《Polymer Engineering and Science》2001,41(9):1636-1643
A new mechanism is described that allows adjustment of the groove geometry in grooved feed extruders. This mechanism enables efficient, continuous and independent change of the groove geometry during the extrusion process. The patented solution of the activated grooved feed section enables one to change the number of grooves, taper angle and, connected with it, groove depth. The paper contains the graphical presentation of the selected results of experimental studies of autothermal extrusion of a medium density polyethylene in an extruder with the grooved feed section in which the groove taper angle, and thus groove depth, was changed during the extrusion process. The influence of changing the groove taper angle in the range from 0 to 5.236 × 10?2 rad and screw speeds ranging from 177 to 279 rev/min on extruder output was studied. The energy efficiency of the extruder was studied as well. 相似文献
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利用EDEM软件对一种普通锥形和两种双锥型螺杆挤出机固体输送段进行模拟.分析了高密度聚乙烯(PE-HD)颗粒在锥形双螺杆挤出机内的运动状态和分布规律.对比分析了3种锥形螺杆挤出的质量流速率、填充率、平均速度、平均压力、平均剪切应力和力矩等参数,给出了普通型和双锥型螺杆挤出机固体输送机理以及主要影响因素.结果表明,相比于... 相似文献
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Krzysztof Wilczyński 《Polymer-Plastics Technology and Engineering》2013,52(3):449-477
A fully predictive computer model has been developed for a single-screw plasticating extrusion (with conventional screws). The model takes into account five zones of the extruder (hopper, solids conveying, delay zone, melting zone, melt conveying) and the die, and describes an operation of the extruder-die system, making it possible to predict a mass flow rate of the polymer, pressure and temperature profiles along the screw channel and in the die, solid bed profile, and power consumption. Moreover, mixing degree, temperature fluctuation and viscoelastic properties of the polymer are estimated. The simulation parameters are the material and rheological properties of the polymer, the screw, hopper and die geometry, and the operating conditions (screw speed and barrel temperature profile). Such a comprehensive approach to the modeling of extrusion creates the possibility of optimizing the process, for example, from the point of view of the quality of extrusion. The model has been verified experimentally for a low-density polyethylene on a 45 mm diameter single-screw extruder. 相似文献
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在单螺杆挤出机中,通过螺杆的轴向振动将振动力场引入聚合物固体输送过程,提出振动力场强化固体输送过程的新概念.以螺槽中运动的物料为对象建立了振动力场强化固体输送过程的数学模型,并获得了物料沿螺槽方向输送的压力(密度)、速度的近似解析解.传统固体输送过程就是当螺杆轴向振动的振幅为零时的特例,此时的压力降与Darnell and Mol 理论一致,但不同的是物料速度及密度沿螺槽方向是变化的,从而修正了Darnell and Mol 固体输送理论.螺杆的轴向振动提高了固体输送平均压力,缩短了固体输送的长度,增加了固体输送角.透明料筒全程可视化实验挤出机证明了螺杆轴向振动确实缩短了物料固体压实输送所需的螺槽长度. 相似文献
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A novel melting model for single screw extruders with a grooved melting zone was established. The whole solid plug, which came from the grooved feed zone, was ruptured and melted mainly by continuously changing the volume of the barrel grooves and the screw channel in the grooved melting zone. A new single screw extruder platform with hydraulic clamshell barrels was constructed to investigate the melting of solid polymer with different combinations of barrels and screws. The melting model was verified by experiments. The results showed that the melting started earlier and finished in a shorter length for single screw extruders with a grooved melting zone than that for conventional single screw extruders and the melting efficiency was improved by introducing a grooved melting zone to a single screw extruder. The theoretical values are consistent with experimental results. The novel single screw extruder with grooved melting zone can dramatically increase the plasticizing efficiency and the throughput. 相似文献
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Jin‐Ping Qu Gui‐Zhen Zhang Hui‐Zhuo Chen Xiao‐Chun Yin He‐Zhi He 《Polymer Engineering and Science》2012,52(10):2147-2156
The pressure establishment in the solid conveying section of a vane extruder was theoretically and experimentally studied in the present article. Based on the structural and conveying characteristics of the vane extruder, a four‐plate model was developed. The effects of the device geometry (eccentricity ε and discharge port β), the polymer properties (different materials), and the operating conditions (temperature and rotating speed) on the pressure were also studied using a visual experimental device. The results showed that the experimental data were highly consistent with the theoretical data, which indicated that the theoretical model was sensible. Considering the optimization design of the device and its processing parameters, the eccentricity ε and the discharge port β of the discharge baffle should be appropriately selected, and the setting temperature of the feeding section should be set to a low value. The rotating speed of the rotor had no significant influence on the pressure establishment. In addition, the thermo‐mechanical history of the vane extruder was shorter than that of the conventional screw extruder. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers 相似文献
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A fully-predictive steady-state computer model has been developed for a single-screw plasticating extruder. Included in the model are a model for solids flow in the feed hopper; a variation of the Darnell and Mol model for the solids conveying zone; a variation of Tadmor's melting model for the melting zone; an implicit finite difference solution of the mass, momentum, and energy conservation equations for the melt-conveying zone of the extruder and die; and a predictive correlation for the extrudate swell at the die exit. A temperature- and shear-rate-dependent viscosity equation is used to describe the melt-flow behavior in the model. The parameters in the viscosity equation are obtained by applying regression analysis to Instron capillary rheometer data. Given the material and rheological properties of the polymer, the screw geometry and dimensions, and the extruder operating conditions, the following are predicted: flow rate of the polymer, pressure and temperature profiles along the extruder screw channel and in the die, and extrudate swell at the die exit. The predictions have been confirmed with experimental results from a 11/2 in. (38 mm) diameter, 24:1 L/D single-screw extruder with a 3/16 in. (4.76 mm) diameter cylindrical red die. High- and low-density polyethylene resins were used. 相似文献