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啮合同向双螺杆挤出过程停留时间分布实验研究 总被引:2,自引:1,他引:2
通过对啮合同向双螺杆挤出过程常规螺纹元件螺杆组合及引入轴向循环段的螺杆组合停留时间的实验研究,分析了轴向循环段的引入对啮合同向双螺杆挤出过程停留时间及其分布的影响。 相似文献
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非啮合双螺杆挤出过程停留时间分布实验研究 总被引:4,自引:0,他引:4
通过对非啮合双螺杆挤出过程常规螺纹纹元件螺杆组合及引入轴向循环段的螺杆组合下的停留时间的实验研究,分析了轴向循环段的引入对非啮合双螺杆过程中停留时间及其分布的影响。 相似文献
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修正了啮合同向双螺杆挤出机中的聚苯乙烯停留时间分布的一维模拟模型。对于输送单元通过C形腔内流体的本构方程推导速度分布,进而得到停留时间分布;引入Carreau—Yasuda模型来描述熔体黏度。在捏合块单元引入轴向分散模型描述该单元的停留时间分布。通过局部停留时间分布模型的修正改进了对双螺杆挤出机全局停留时间分布的预测。模拟研究了螺杆转速及喂料速率对停留时间分布的影响。模拟结果的峰形、最小停留时间、平均停留时间与实验测量相符合。 相似文献
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啮合异向双螺杆挤出过程停留时间分布实验研究 总被引:2,自引:0,他引:2
通过对啮合异向双螺杆挤出过程常规螺纹元件螺杆组合及引入轴向循环段的螺杆组合停留时间的实验研究,分析了轴向循环段的引入对啮合异向双螺杆挤出过程停留时间及其分布的影响。 相似文献
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应用全析因设计方法,研究了捏合块角度、比产率(喂料速率/螺杆转速)和螺杆转速对双螺杆挤出机机筒不同位置的延迟时间和平均停留时间的影响,考察了各因素之间的交互作用。结果表明,在所选取的操作条件下,螺杆转速对延迟时间和平均停留时间的影响最大,捏合块角度与比产率的影响程度相近。3因素两两交互作用对延迟时间的影响程度由大到小依次为捏合块角度与比产率、螺杆转速与比产率、捏合块角度与螺杆转速;对平均停留时间的影响由大到小依次为比产率与螺杆转速、捏合块角度与比产率、捏合块角度与螺杆转速。3因素3阶交互作用对平均停留时间的影响比较显著。 相似文献
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聚合物熔体在异型材三维动态挤出口模内的停留时间分布 总被引:1,自引:1,他引:1
利用ANSYS软件对受口模入口处周期性振动的压力驱动的聚合物熔体在“Y”形和“L”形异型材挤出口模内的停留时间分布进行了数值模拟。设熔体流动为三维等温广义牛顿幂律流动,在求得速度场后,应用路线示踪法跟踪流场中任一粒子的流动轨迹,进而求得熔体在口模中的停留时间分布。通过改变振动参数再重复计算,总结出振动参数对停留时间分布的影响规律。结果表明:压力的振动能有效地缩短熔体在口模内的停留时间,振幅和频率越高则停留时间越短,而且在靠近口模流道壁面处停留时间的缩短最明显,表明振动的引入可以降低壁面附近的流动阻力,使截面上的流速更平稳,从而改善挤出制品的表观质量。 相似文献
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在分析流化床内的气固流动特性和各种流化床的流体动力学数学模型的基础上,建立KLDH数学模型,以此可计算流态化炉内密相段与悬浮段的物料停留时间分布。结合流态化炉的实际操作参数,计算炉内物料的停留时间。 相似文献
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Haixia Fang Frej Mighri Abdellah Ajji Philippe Cassagnau Said Elkoun 《应用聚合物科学杂志》2011,120(4):2304-2312
The objective of this work was to investigate the flow behavior of pure polymers and blends, especially miscible polymer/polymer systems, in a corotating twin‐screw extruder (TSE) using an online fluorescence monitoring device. An immiscible blend was also studied for the sake of comparison. The fluorescence signal was obtained by using synthesized fluorescence tracers added to the melt at very low concentrations. These tracers consisted of two styrene‐maleic anhydride copolymers (SMA) labeled with anthracene. The investigated blends were SMA8 (8 wt % of MA in SMA)/polystyrene (PS), SMA14 (14 wt % of MA in SMA)/styrene acrylonitrile copolymer (SAN), and poly(methyl methacrylate) (PMMA)/ethyl acrylate‐methyl methacrylate copolymer (PMMAEA). The residence time distribution (RTD), the mean residence time (t ), the dimensionless variance (σθ2), the Peclet number (Pe) and the fluorescence peak intensity distribution of pure polymers and binary polymer systems were investigated and interpreted in terms of polymers rheological properties. It was observed that polymers presenting higher viscosity or higher pressure showed longer residence time. A difference in behavior was also observed for the RTD of miscible and immiscible blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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Yijie Gao Benjamin J. Glasser Marianthi G. Ierapetritou Alberto Cuitino Fernando J. Muzzio Jean W. Beeckman Natalie A. Fassbender William G. Borghard 《American Institute of Chemical Engineers》2013,59(11):4068-4076
Rotary calcination is widely used in catalyst manufacturing and many other industrial processes. In this article, the influence of operational variables and material properties on the mean residence time (MRT), hold up, and axial dispersion was investigated in a pilot plant rotary calciner. Residence time distributions (RTD) of spherical, cylindrical, and quadrilobe catalyst particles were measured and contrasted. The Saeman's model was successfully applied to predict the experimental bed depth and the MRT as particles flowed through the calciner. It was observed that increasing the feed rate did not significantly affect the MRT. Results for the different particles indicated that cylinders and quadrulobes exhibited less axial dispersion than spheres due to the decreased flowability. A reliable method was developed to provide a reasonable RTD prediction in rotary calcination systems. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4068–4076, 2013 相似文献
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以低分子量的聚丙二醇为流动介质、酸性橙的N,N-二甲基乙酰胺溶液为示踪剂,采用脉冲响应法测定了螺旋型微通道(MC)反应器内的停留时间分布(RTD),验证了平行多釜串联(PTIS)模型与RTD实验数据的匹配性,系统考察了MC长度和Reynolds数(Re)对RTD的影响,并讨论了流体径向速度分布指数y和Peclet数(Pe)的变化规律。结果表明,RTD随MC长度的增加而变窄。当通过降低黏度来增大Re时,RTD随之变窄。当通过增大流速来增大Re时,若管径较大,则RTD随之变窄。但若管径较小且管长不长时,则RTD随Re的增加而变宽;如管长较长,则RTD随Re(或流速)的增加先变宽后变窄,即存在临界Reynolds数(Rec)。RTD的这些变化规律表明,二次流动和径向分子扩散对细小管径的MC的RTD有显著的影响。 相似文献