共查询到19条相似文献,搜索用时 109 毫秒
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龚浏澄 《现代塑料加工应用》1991,(1):53-55
挤出与注塑是塑料成型加工中应用最广的两类成型工艺,螺杆是其关键部件,因而对螺杆结构的研究是至关重要的。就单螺杆而言,目前已有各式各样的螺杆,近年来国外在原有的分离型、混炼型螺杆的基础上,又开发出螺杆套螺杆的双螺杆型,压缩—减压型的单螺杆。压缩—减压型螺杆又有能量传递式(ET)螺杆和波状螺杆。波状螺杆与普通单螺杆一样,仍分固体 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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波状注塑螺杆熔体输送机理的研究 总被引:2,自引:0,他引:2
本文在综合分析国内外波状螺杆研究成果的基础下,根据注射机预塑过程的特点,建立了更真实地反映波状螺杆工作机理的三维理论模型。在模型中将背压做为一个重要变量予以考虑,采用分段的二维有限元与差分迭代相结合的方法,对等温幂律流动的速度场,压力场和应力场进行了求解,在计算的基础上又进一步分析了波状螺杆几何参数、预塑工艺条件和物料流变参数对熔体输送总流率、压力降、槽向压力分布及扭矩和能耗的影响。对部分计算结果在注塑机实验台上进行的实验验证表明:采用本文理论模型的计算结果与实验结果相近,说明本文的理论模型和计算方法具有一定的工程实用性。 相似文献
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挤出过程物料停留时间分布的在线测量和模型 总被引:2,自引:1,他引:2
采用荧光检测方法在线测量了同向双螺杆挤出机中物料的停留时间分布(τ),研究了示踪剂浓度和电压信号强度的关系以及螺杆转速(ω)和喂料速率(Q)对双螺杆挤出机τ的影响,比较了多级理想混合(TIS)模型、回流多级理想混合(BFC)模型和双回流多级理想混合(DBFC)模型描述该挤出机的符合程度。结果表明,当9为10.0~16.0kg/h,ω为60~120r/min时,示踪剂浓度和电压信号具有线性关系;ω和Q对平均停留时间有显著的影响,对轴向混合强度的影响不明显。BFC模型和DBFC模型适合描述双螺杆挤出机的流动状况,而TIS模型偏差较大。 相似文献
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首先建立注塑螺杆的模拟及优化平台,该平台以Injection Molding Plastification(IMP)软件为基础,结合DOE(实验设计)方法,将不同螺杆的模拟结果进行DOE分析和优化。重点对常规三段式螺杆的计量段结构进行了研究,分别采用模拟优化和实验优化的方法对计量段槽深和导程进行了优化。并将两种优化方法的优化结果进行对比,结果分析表明:模拟与实验优化结果比较接近,初步形成模拟与实验相结合的优化思路。在螺杆的模拟优化之前,对IMP软件的可靠性和准确性进行初步验证,通过比较模拟和实验获得的螺杆沿程压力、螺杆扭矩,结果表明该软件基本上能够较准确地反映实际加工过程。 相似文献
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Residence time in a single screw free helix extruder using a new solution to the biharmonic equation
Gregory A. Campbell Sirisha Bomma Samuel St. John Shaji Chempath Diana Hunt Ross Taylor David L. Powers Mark D. Wetzel 《Polymer Engineering and Science》2021,61(1):184-200
A new analytical solution for the biharmonic equation was developed for single screw extrusion cross-channel fluid mechanical flow. This analysis led to a quantitative model for residence time distribution when combined with the historic solutions of the drag and pressure flow in the rectangular channel in the single-screw extruder. The focus of the theoretical and experimental investigation here was to examine how closely the new analytical solution correlated with experimental residence time data for a free-helix extruder. This new extrusion device was operated as both a conventional extruder and a more positive displacement device by using only helix rotation as the pump. The Moffatt eddies that occur in the quiescent corners of the rectangular channel with screw rotation were found to have a strong effect on the residence time of the extruder. Because there were no quiescent corners for the free-helix flow there was essentially no residence time tail for this mode of extruder displacement. The theoretical results for a sheet of dye spanning the screw channel width and dye “blobs” were compared with experimental results for both modes of operation. In all cases, the experiments and the theory predictions were essentially consistent. 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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This paper presents an experimental study of residence time distribution (RTD) analysis by pulse response technique in a continuous Couette flow device with rotating inner cylinder and stationary outer cylinder. Two kinds of experimental tests using pulses of tracer dye solution and particles resulting from a fast precipitation were performed in the region near the critical Taylor number characterizing boundary between laminar and laminar vortex flow. For most experiments performed in laminar and laminar vortex flow regime around the critical Taylor number over the ranges 0 < Ta < 120 and 0 < Re < 5.5 the normalized response can be described by a dispersion model. The results of the critical Taylor number as characterized by the minimum dispersion number appear consistent with both theoretical predictions and other empirical observations. 相似文献
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讨论了挤出机螺杆计量段的优化设计问题。应用粘性流体动力学基本方程,分析了聚合物物料在螺槽中的流动。以单位产量能耗最小为优化目标,建立简化的挤出机计量段螺杆优化设计的数学模型,应用约束随机方向法求解。结果表明,螺槽深度、螺纹棱顶宽度、螺纹棱顶与机筒间隙和螺纹升角均位于或接近于献中所建议的最佳取值范围。 相似文献