共查询到18条相似文献,搜索用时 125 毫秒
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采用流体力学计算软件Fluent,在对销钉机筒冷喂料挤出机熔融段和计量段的胶料进行三维流动数值模拟的基础上,考察螺杆转速、反向压差、销钉数量、销钉排间距和螺槽深度对挤出量和螺杆转矩的影响。结果表明,螺杆转速是影响挤出机功耗的首要因素,随着转速增大,挤出量增大,功耗和功耗比(螺杆转矩与挤出量之比)下降;反向压差对挤出量、螺杆转矩和功耗比有一定影响,反向压差越大,功耗比越大;每排销钉数量对对功耗比影响不大;销钉排间距对挤出机功耗比有较为明显的影响,若只考虑产量和功耗,则销钉排间距越大越好。 相似文献
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国外橡胶挤出理论研究简介 总被引:3,自引:0,他引:3
概述了近年来国外有关橡胶挤出理论的研究情况。介绍了普通型、强力剪切型、销钉机筒型及传递型橡胶冷喂料挤出机螺杆螺槽内胶料流动特性理论研究的动向。 相似文献
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使用三种不同的橡胶-炭黑胶料在一台模型销钉机筒挤出机上进行实验,对胶料的流动、推进和混合特性进行研究,三种胶料分别是SBR/BR(丁苯橡胶/丁二烯橡胶)乘用轮胎胶料,NR(天然橡胶)载重轮胎胶料和NBR(丁腈橡胶)工业制品胶料。实验对螺杆上没有销钉或挡板/沟槽的普通挤出机,螺杆上有挡板或沟槽的挤出机以及销钉机筒挤出机分别进行了对比.发现在螺杆上增加挡板可改善胶料的混合/均匀性,但同时会降低胶料的推进能力:采用销钉则既可改善混合/均匀性又不会影响推进力。均匀性最好的是乘用胎胎面胶料,均匀性最差的是NBR工业制品胶料。 相似文献
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销钉挤出机在橡胶工业上起着重要的作用。本文给出了销钉挤出机内物料的流动和生热量的模型。这模拟模型是以流体动力润滑理论为基础的,并且运用了修正过的流动网络分析(FAN)数值分析技术。本方法创新之处在于它考虑了由粘流引起热分散对热传导的影响以及在与FAN技术等同的精确度上热的转换。这一方法已用于计算螺杆挤出机内牛顿流体的压力场,速度场和温度场。我们研究了粘性流体生热对销钉机筒内螺杆推进特性的影响。随着温度对粘度依赖性的增加,销钉挤出机的物料传递能力下降。本文也考虑了销钉对热特性的影响。 相似文献
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美国RMS公司的PME冷喂料销钉式挤出机是供加工橡胶胶料使用的。该冷喂料销钉式挤出机的设计准则包括:机筒销钉插入于螺杆螺纹槽内以破碎和混匀胶料;在该机筒内部有可替换的增强村层;带有喂料辊的高进料料斗能保证连续向该机喂入胶片或胶条;在上述料斗,机筒和螺杆内部的加热和冷却通路使之具有温度有序分布的特性;胶料的良好混合能在低于一般加工温度下提高挤出率等。此外,该公司声称所用螺杆是以美国钢铁学会(AISI)4150的主材料加以制作的,而上述高位料斗是装在齿轮减速箱与销钉机筒之间的钢组合件总成。再之,宽敞的料斗目能… 相似文献
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通过建立简化的销钉机筒挤出机塑化段物理模型,从流变分析中的能量方程出发,导出销钉机筒挤出机塑化段温度的传热模型;结合试验数据,拟合出挤出温度随螺杆转速变化的曲线。结果表明,曲线可分为急速增长段、平缓增长段和稳定增长段3部分,且平缓增长段是挤出温度、质量和能耗综合指标最佳的区间。 相似文献
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销钉机筒挤出机螺槽横截面内流体流动与混合的研究 总被引:1,自引:0,他引:1
在一定简化条件下,对销钉机筒挤出机螺槽横截面内的流场及混合均化效果以及销钉位置对流场和混合均化效果的影响进行了数值与实验研究。提出了流场中某点混合均化效果、整个流场平均混合均化效果以及混合均化效果统计分布的数值计算与评价方法。数值分析结果与实验结果具有较好的一致性。结果表明,销钉对物料具有明显的强化流动与混合均化的作用:销钉愈接近于螺棱,强化混合均化的效果愈显著:有销钉结构较无销钉结构的平均混合均化效果提高2.5%-5.6%;有销钉结构随着挤出时间的增加,混合均化效果不断提高,无销钉结构随着挤出时间的增加,当混合均化效果达到一定值后则不再提高。 相似文献
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非啮合双螺杆挤出过程常规螺纹元件流道三维流场分析——等温牛顿模型 总被引:10,自引:2,他引:8
利用ANSYS有限元分析软件对非啮合双螺杆挤出机螺纹元件中的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,分析了不同几何条件及操作条件对输送特性及混合能力的影响。 相似文献
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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
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Takamasa Fukuoka 《Polymer Engineering and Science》2000,40(12):2524-2538
A newly designed extruder reactor for grafting vinyl monomers onto polyolefins was studied experimentally and theoretically. The process was made up of a self‐wiping co‐rotating twin screw extruder with a separated reaction zone and two vent zones. The reactive extrusion was performed using a linear low density polyethylene, vinyltrimethoxysilane and di‐t‐butylperoxide under different operation conditions. For the purpose of process analysis, we built a computer simulation based on the reaction kinetics and rheological models studied in the preceding paper. The flow field in the extruder was calculated by the flow analysis network (FAN) method with non‐isothermal non‐Newtonian flow conditions. The iterative procedure was organized to predict local pressure, filling factor, cumulative residence time and temperature along the extruder. Furthermore, we succeeded in representing the profiles of reaction conversion and shear viscosity. Calculated results showed good agreements with the experimental data. 相似文献
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The flow of a polymer and the associated heat transfer in a fully intermeshing, co‐rotating twin screw extruder are investigated numerically. The control volume technique is used for numerical modeling and simulation, considering both Newtonian and non‐Newtonian fluids. The velocity distributions in the screw channel are compared with experimental resultlsf and good agreement is obtained. Owing to limitations arising from the physical aspects of the problem, the numerical results show that not all operating conditions are feasible. A feasible domain, in terms of screw speed and mass flow rate, in which the extruder operation is satisfactroy, is obtained for pure starch. To improve the applicable range of this model, an axial formulation is adopted for the translation region that characterizes the domain away from the intermeshing zone of the extruder. This model yields results consistent with the earlier down‐channel model while the feasibility region is extended towards lower mass flow rates. For the upper limit, a physicdal restriction arises in terms of the maximum flow rate for a pressure rise in the extruder. Thus, the model can be used for simulating a wide range of operating conditions while retaining the appropriate physical behavior of the process. 相似文献
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Maleic anhydride was grafted onto a polypropylene‐type thermoplastic elastomer PER by reactive processing with a screw extruder, and a maleated PER (MPER) was prepared. Aiming at ionic crosslinking, magnesium 12‐hydroxy stearate (MgStOH), zinc oxide (ZnO), and zinc sulfide (ZnS), and aiming at covalent crosslinking, melamine as an amino compound, and Epocizer and GRYCI‐ALE as epoxy compounds, were added to the MPER, melt‐mixed by use of the screw extruder, and crosslinked compounds were obtained. The rheological properties such as capillary flow properties and dynamic viscoelasticities of the compounds were measured and their melt processabilities were evaluated. The degree of crosslinking was in the order of epoxy compounds > MgStOH > melamine > ZnO, ZnS > MPER (blank). In the case of the compound with MgStOH of a moderately high degree of crosslinking, the non‐Newtonian behavior is remarkable and the die swell ratio is low and suitable for extrusion. However, in the case of compounds with epoxy compounds of an excessive degree of crosslinking, fine extrudate cannot be obtained due to the lack of fusion and the control of degree of crosslinking is necessary. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 762–773, 2002 相似文献
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《塑料、橡胶和复合材料》2013,42(8):376-380
AbstractExperimental effect of a screw disc clearance size on the homogenisation level and the mechanical properties of extrudate obtained using the mixture of original low density polyethylene (LDPE) and commercial LDPE recyclate were discussed in the present paper. For the purpose of experiments a screw disc extruder was applied. Some tensile tests results and photographs of the extrudate cross-sections obtained at different clearance settings were presented. The results show that the mixing in the conical screw disc zone was carried out more thoroughly than in a helical channel of a single screw extruder. Plasticising in the disc zone of a screw disc extruder makes it possible to obtain extrudate with better properties than in the case of classical extrusion. 相似文献