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采用有限元分析软件POLYFLOW对发生在Haake密闭式混合器中的双组分聚合物熔体共混过程进行了二维等温数值模拟,并进行了实验验证。首先采用仅和流场有关的黏度模型对共混过程进行了数值模拟,模拟结果与实验结果符合较好。进而又考虑了共混体系中组分含量对共混体系黏度的影响,对原来的黏度模型进行了修正,修正后的数值模拟结果和实验结果更接近。通过利用数值模拟的方法进一步获悉了双组分聚合物体系对流混合的规律。 相似文献
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Haake混合器中双组分聚合物熔体共混过程的数值模拟研究 总被引:2,自引:0,他引:2
采用有限元分析软件POLYFLOW对发生在Haake密闭式混合器中的双组分聚合物熔体共混过程进行了二维等温数值模拟,并进行了实验验证。首先采用仅和流场有关的黏度模型对共混过程进行了数值模拟,模拟结果与实验结果符合较好。进而又考虑了共混体系中组分含量对共混体系黏度的影响,对原来的黏度模型进行了修正,修正后的数值模拟结果和实验结果更接近。通过利用数值模拟的方法进一步获悉了双组分聚合物体系对流混合的规律。 相似文献
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SiC冶炼炉温度场有限元分析 总被引:2,自引:0,他引:2
采用有限元分析方法对Acheason炉内温度场进行研究,进而采用ANSYS数值模拟软件对冶炼炉内工分布进行模拟,得到了冶炼炉内温度分布的模拟图,分析了炉内的温度分布规律及其对SiC的生成和产率的影响,并提出了扩大SiC生成温度区域的.措施。 相似文献
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换热器传热数值模拟的两个假设 总被引:1,自引:0,他引:1
对管壳式换热器的数值模拟所采用的数值模型发展过程进行了详细介绍,列出了管壳式换热器壳程和管程数值模拟所取得的研究成果。接着对换热器的整体传热模拟作了简化,提出两种假设,并举例进行数值模拟验证,结果表明:温度场的分布与假设相近。这样对换热器的数值模拟给出一个新的思路。 相似文献
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全隐式聚驱数值模拟软件研制 总被引:1,自引:0,他引:1
建立了三维三相四组分的聚驱数学模型,考虑了聚合物溶液的剪切特性:渗透率下降、吸附、不可及孔隙体积等主要物理化学机理。对数学模型进行数值求解时,采用全隐式的有限差分格式在时间和空间上进行离散,将离散后的非线性方程组线性化,再数值求解线性方程组。在PC-Linux环境下,基于黑油模拟器重新编写了计算雅可比矩阵和线性方程组的求解程序,开发出了全隐式聚驱数值模拟软件(DQPOLY1.0),将水驱、聚驱数值模拟一体化,可用于实际区块的数值模拟计算。 相似文献
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用数值方法模拟非均质材料成为近20多年来细观力学的主要手段之一。本文综述非均质材料有效模量的数值模拟的研究进展,介绍了模拟非均质材料的主要的数值方法与所采用的计算模型,评述了数值方法的特点,最后对非均质材料有效模量数值模拟的前景做了展望。 相似文献
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民用飞机复合材料结构设计时必须考虑复合材料层合板的冲击损伤.通过试验测量和数值模拟两种方法分析碳纤维增强复合材料层合板低速冲击损伤后的剩余压缩强度,试验采用标准试验规范进行测量,数值模拟分析采用层内渐进损伤模型和层间Cohesive模型模拟分析层合板冲击损伤以及剩余压缩强度.数值模拟与试验结果对比表明,该数值模拟分析方... 相似文献
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计算流体动力学(CFD)及其软件包在双螺杆挤出中的应用 总被引:13,自引:0,他引:13
从数学模型、软件包的应用和数值模拟对象(即整根螺杆、熔体输送段、混合以及反应挤出等)三个方面介绍了计算流体动力学(CFD)及其软件包在双螺杆挤出中的应用,并讨论了双螺杆挤出加工数值模拟中尚特解决的问题。 相似文献
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3‐D numerical simulations for polycondensation of poly(p‐phenylene terephthalamide) in twin screw extruder 下载免费PDF全文
Poly(p‐phenylene terephthalamide) (PPTA) is a typical high‐performance fiber and usually synthesized by low temperature solution polycondensation in twin screw extruder. During the reactive extrusion, flow behavior, rheokinetics, and temperature are highly coupled, which makes it difficult to ensure the quality of product. In the present work, the rheokinetics of the PPTA solution is established by experiments and its reactive extrusion is investigated via 3‐D numerical simulation. The flow pattern, molecular weight distribution and temperature have been investigated for the extruders with three different elements, i.e., full flight screw (FF), kneading block (KB), and screw mixing element (SME). The results indicate that the unique flow characteristic of different screw elements affects mixing experience of the reactants and further the PPTA qualities. By numerical simulation, it shows the temperature increase within the tested extrusion stage is 7 K and reaction heat is found the main energy source for extrusion stage. Furthermore, heat removal method is verified with consideration of industrial production process. The numerical simulation work also discusses the reaction and mixing process in the extruders with three combined screws. The results show the introduction of more reverse FF and KB elements can lead to higher quality of PPTA. POLYM. ENG. SCI., 57:1252–1261, 2017. © 2017 Society of Plastics Engineers 相似文献
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介绍一种动静环式过滤机的结构原理,运用ANSYS有限元软件对动静环式过滤机静环的受载特点进行模拟,对其变形进行比较。有限元模拟结果表明,相比较于2 mm的静环厚度设计,3 mm至5 mm的静环厚度更能有效地避免挤压变形,为设计方案的可靠性提供了依据,提高了过滤机的使用寿命。 相似文献
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单螺杆挤出过程熔体输送段数值模拟方法 总被引:3,自引:0,他引:3
综述了应用于螺杆挤出成型过程熔体输送段数值模拟的各种计算方法,根据挤出过程聚合物流场控制方程,介绍了几种有代表性的聚合物本构关系,包括线性黏弹性和非线性黏弹性本构方程。概述了有限差分法、有限元法、有限体积法和边界元法等数值计算方法的特点和应用范围,并针对聚合物熔体流动模拟中的迭代收敛性和稳定性、耦合和解耦合、高Weissenberg数等问题进行了讨论,指出应该根据研究目的和实际情况选择适宜的本构方程和数值方法。 相似文献
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In a plasticating screw extruder, a polymer melt forms in the melting zone of the extruder. Pressurization of the molten polymer takes place in the melting and the metering sections so that the melt can flow through the restricted passage of the die and assume a desired shape. In a melt fed extruder, the throughput is governed by the pressure rise over the entire length of the extruder. The pressure developed in the screw channel may also be employed in rapid filling of molds, such as those in injection molding. When the geometry of the screw, the barrel temperature, and the die are selected, a unique set of operating parameters arise for a particular flow rate or screw speed. In the present study, numerical and analytical methods are used to calculate the transport in the extruder and the pressure drop in the die. An iterative numerical method based on solving the equations of motion and energy in the screw channel and a correction scheme to couple the die with the screw channel is discussed. The numerical algorithm is capable of handling an arbitrary variation of the viscosity of the polymeric fluid with the shear rate and temperature. The results obtained by simulating the fluid flow in the screw channel are compared with available numerical and experimental results in the literature, indicating good agreement. The performance characteristics of the extruder, for chosen thermal boundary conditions and screw geometry, are presented for different die geometries and different fluids. The important considerations that arise in the numerical simulation of the extrusion process are also discussed. 相似文献
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为提高螺压推进剂成型工艺过程的安全性,从剪切流动、绝热压缩和过热分解等视角,对推进剂在单螺杆压伸成型工艺过程中发生危险的可能性进行论述。系统地分析了药料在螺杆和模具内的流动状态,通过模拟实验,研究了推进剂在压伸过程中的热分解(着火)温度,通过实验数据分析了热分解的原因。结果表明:在药料剪切强度下降的情况下,固体床的断裂将意味着压伸的失败;在排气不畅的情况下,压伸过程的断料有可能形成绝热压缩而引发严重后果。 相似文献
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在传统的三螺杆挤出机的基础上,设计了一种新型偏心三螺杆挤出机。该三螺杆挤出机中具有螺杆几何结构偏心、螺槽构型呈梯度变化特殊以及较高的面积利用系数等特征。利用有限元法对聚丙烯(PP)熔体在新型偏心三螺杆挤出机中流动和混合规律进行三维数值模拟,给出偏心三螺杆挤出机中压力和速度分布规律,计算了3种偏心螺杆挤出流场的停留时间分布、分布指数、分离尺度、最大剪切应力等混合表征参数。结果表明,螺杆偏心距不仅决定了螺杆端面形状,也改变了螺槽梯度的变化程度。随着螺槽梯度的逐渐减小,挤出机内粒子团聚效应逐渐降低、物料剪切作用逐渐增强。在3种新型偏心三螺杆挤出机中,偏心距e=3 mm的新型偏心螺杆挤出机的混合性能相对较好。 相似文献
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In polymer extrusion processing, mixing enhancement is an important consideration when an extruder screw is being designed. There are a variety of mixing elements used in the extrusion industry, with little consensus about what differentiates a good mixing section from a poor one. However, good mixing is important for homogenizing the material structure and temperature profile in the flow channel. This article presents a numerical analysis of the role of screw geometry in mixing in a cooling extruder. Four geometries, typical of those used by the extrusion industry, are assessed by the study of the polymer melt flow and heat transfer in the screw channels. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献