基于EDEM的双卧轴搅拌机搅拌工艺 对比研究

分析了搅拌工艺对水泥混凝土性能的影响,在此基础上,研究不同搅拌工艺对双卧轴搅拌机物料搅拌均匀性的影响。利用EDEM软件对一次投料法、水泥砂浆法和水泥裹砂石法三种不同搅拌工艺对物料搅拌均匀性的影响进行了模拟仿真。仿真结果表明:二次搅拌工艺搅拌物料均匀性比传统的一次搅拌工艺优越,其中,采用水泥砂浆法物料搅拌均匀性最好,而且可降低搅拌时间。     

双排叶片数目对搅拌质量影响的研究

为了探究合理数目的双排叶片对搅拌质量的影响,根据双卧轴搅拌机的本身结构特点。运用离散元分析软件EDEM,仿真物料在拌筒内运动的过程。结果表明:在搅拌质量和搅拌效率方面,一半双排叶片数目的搅拌装置和全部双排叶片数目的搅拌装置仿真效果基本一致。     

三螺杆分散混合数值模拟及实验分析

为了研究平行同向啮合三螺杆挤出机的分散混合效果,采用离散元法对三螺杆挤出机中聚丙烯(PP)/低密度聚乙烯(PE-LD)两种塑料颗粒在加料段的混合情况进行数值模拟.首先建立了三螺杆挤出机的三维模型,在EDEM软件中仿真出不同螺杆转速下挤出机的混合效果,通过对收集盒分层处理计算得出混合过程中混合均匀度的变化趋势.分析结果表...     

基于离散元的落地熟料库贮料压力分析

采用离散元EDEM软件,建立大直径落地熟料库偏心卸料动态力学模型,模拟熟料库在使用过程中的卸料状况;研究熟料颗粒流动引起的仓壁动态压力效应;指出在熟料作用下库底廊道顶部纵向压力的不对称性,以及廊道侧壁高度范围内侧贮料压力的不均匀性;从而找出仓壁和廊道的不同受力特点。     

磁粒研磨中磁性磨料的动力学行为仿真研究

为了探究磁粒研磨中磁性磨料的最佳动力学参数,利用有限元软件ANSYS Maxwell结合离散元软件EDEM,对磁粒研磨加工过程进行动态仿真。首先进行微观参数标定,得到了磁性磨粒离散元仿真所需的参数,最终确定滑动摩擦系数为0.9、滚动摩擦系数为0.109为最优的参数组合。在此参数基础上,对磁粒研磨加工过程进行动态仿真。结果表明：在其他条件一定的情况下,磁场转速越高,单位时间内磁性磨粒与管件表面之间的作用次数越高,加工效率越高。通过加工实验,得到了在不同加工参数下表面粗糙度数据。模拟仿真结果与实验结果的变化趋势具有一致性,验证了利用数值分析的手段对磁粒研磨加工过程进行理论分析的可行性。     

基于EDEM仿真的输送带头部漏斗堵料分析和改造

针对某电厂转运站煤场输送带头部漏斗堵料问题，通过料性分析和标定试验并结合EDEM离散元软件仿真技术，设定了煤料运行仿真参数，仿真了漏斗堵料状况，并根据仿真结果在漏斗上设置了挡板以解决堵料问题，并以仿真结果验证了改造效果。根据仿真改造模型对头部漏斗进行了改造，实际运行结果证明了改造效果良好，节约了改造时间和成本。     

半圆摆推块式篦冷机熟料输送性能研究

本文自主设计了一种半圆摆推块式篦冷机,解决了水泥熟料在输送过程中存在的料层离析、搅拌能力差及回料等问题。采用颗粒离散元(EDEM)软件对篦冷机输送水泥熟料运动过程进行仿真,完成了对半圆摆推块式和SF型推动棒式两种篦冷机水泥熟料输送过程的模拟,分析了篦冷机输送效率与翻转搅拌能力。结果表明,半圆摆推块式篦冷机这种摆推熟料输送方式,可提高水泥熟料的输送及冷却效率,对新型篦冷机的发展具有理论意义和实用价值。     

物料无桨混合过程数值模拟

目前物料混合主要采用有桨混合方式,该方法容易使物料受到较大摩擦作用。为了解决这一问题,本文对无桨滚筒混合工艺过程进行探索研究。采用离散元软件EDEM模拟无桨滚筒对两种物料的混合过程,分析混合过程中物料的运动特征,通过定义颗粒混合均匀性指数来定量表征混合均匀程度,分析了不同填料（10000~20000个颗粒）和转速（7~22r/min）对混料均匀性的影响规律,并对物料受力情况进行了定量分析。研究结果表明：在无桨滚筒混料过程中,可以实现对两种物料的混合,且随着转速提高,物料能较快达到均匀。在混合过程中物料受力呈波动式变化,其中最大受力小于0.6N,稳定在0.1~0.35N;物料受力平均值小于0.015N,稳定在0.005~0.01N;最大受力是平均受力值的20~30倍;且随着填料和滚筒转速增加,物料的受力略有增加。     

剪切变稀体系同心双轴搅拌釜内的气液分散模拟

气液搅拌设备因其良好的适用性被广泛应用于过程工业中。为更好地比较不同工况下剪切变稀体系中的气液分散情况,通过实验研究整体气含率和相对功耗确定适宜的转动模式,进而模拟研究表观气速、体系黏度、搅拌转速对气含率和气泡尺寸的影响。结果表明,相同功率下内外双桨反向旋转模式在理想气液分散条件下,相较于单轴内桨和内外双桨同向旋转模式具有更高的气含率和更好的气体泵送能力;表观气速的增加有利于气泡的均匀分散,但气泡尺寸也会随之增大;有效黏度的增加使得搅拌桨的影响区域变小,不利于气泡的均匀分散,气泡尺寸也随之增大;搅拌转速的增加使得循环涡流的影响区域变大,高气含率区不断扩大。     

剪切变稀体系同心双轴搅拌釜内的气液分散模拟

气液搅拌设备因其良好的适用性被广泛应用于过程工业中。为更好地比较不同工况下剪切变稀体系中的气液分散情况,通过实验研究整体气含率和相对功耗确定适宜的转动模式,进而模拟研究表观气速、体系黏度、搅拌转速对气含率和气泡尺寸的影响。结果表明,相同功率下内外双桨反向旋转模式在理想气液分散条件下,相较于单轴内桨和内外双桨同向旋转模式具有更高的气含率和更好的气体泵送能力;表观气速的增加有利于气泡的均匀分散,但气泡尺寸也会随之增大;有效黏度的增加使得搅拌桨的影响区域变小,不利于气泡的均匀分散,气泡尺寸也随之增大;搅拌转速的增加使得循环涡流的影响区域变大,高气含率区不断扩大。     

基于离散元方法的差动自清洁混合器混合特性研究

采用离散元方法对LIST卧式差动双轴搅拌设备内高密度聚乙烯（PE?HD）填充碳酸钙复合材料的混合过程进行了仿真模拟,研究了不同加料速率及不同转速条件对该类自清洁混合器混合腔内物料充满度、物料停留时间分布及混合均匀程度的影响。结果表明,该类自清洁混合器的轴向输送能力主要由后续物料的推动作用实现,采用高速轴转速40 r/min,加料速率为10 kg/h的工艺参数可以获得最佳的混合均匀程度。     

Mixing and Heat Transfer of Granular Materials in an Externally Heated Rotary Kiln

A heat transfer model based on the discrete element software EDEM and the secondary development tool C++ is developed to simulate the mixing and heat transfer process of particles under different parameters. This model is validated by comparison with experimental data and proved reasonable. It aims to study the heat transfer law of flowing particles in an externally heated rotary kiln and reveal the correlation between mixing and heat transfer from the mechanism. The results show that the combination of the total contact area between adherent particles and the drum wall, the mean temperature difference between adherent particles and the drum wall, the total contact area between particles, and the mean temperature difference between particles affect the heat transfer process. Changes in the temperature differences caused by the mixing rate dominate the heat transfer at different speeds or filling rates.     

回转干馏炉内二组元颗粒混合机理及混合度分析

采用非等径二组元颗粒,用圆形滚筒模拟回转干馏炉,研究回转干馏炉转速对颗粒径向混合的影响。以滚筒径向颗粒Lacey指数作为混合指数,对5种不同转速下滚筒侧表面颗粒的混合指数与混合机理进行研究,对比分析了混合指数的变化趋势。结果表明：在圆形滚筒混合器内1/6填充率、倾角为0°的情况下,在转速为13.3 r/min时混合度优于其它转速,以对流混合与扩散混合为主;通过对混合质量与混合机理综合分析,得颗粒混合呈现“双振荡趋势”。     

Effectiveness of operation of a DVKh-1000 mixer in the production of electrical periclase powders

Conclusions The DVKh-1000 mixer provides a completely satisfactory degree of uniformity of the chemical and grain size compositions of the material in production of electrical periclase powders. The optimum conditions are obtained with a weight of charged material of 1.4–1.6 tons and a mixing time of 20 min. The coefficient of averaging is 0.60–0.80 for the content of the impurity CaO and 0.64–0.86 for the grain size composition.With a change in the requirements of the standard for grain size composition of electrical periclase powders and also with a change in the method of their production the optimum operating conditions of the mixer may be established on the basis of special additional investigations.The use of methods of geometrization of quality criteria in mineral resources for evaluation of the degree of uniformity of a material in mixing made it possible to establish an effect consisting of the fact that such properties as plasticity and viscosity characteristics of the aggregate condition of a substance (solid, liquid, gaseous) are revealed in the geometric features of the change in quality criteria and physical and technical characteristics of the pulverized and bulk material. This effect explains the existence of some limit of uniformity in mixing of materials with a different degree of variability of its quality criteria. The numerical value of this limit is determined by the physical properties of the material and the design features of the mixing equipment. For the investigated material and type of mixer this limit is 0.06–0.08%.Translated from Ogneupory, No. 8, pp. 41–45, August, 1988.     

Characterization of transverse mixing in a screw mixer by image analysis

Transverse mixing of particles in a screw mixer is investigated by a digitized image analysis method coupled with a solidification technique. The effects of screw rotation speed, filling level, and particle size on the transverse mixing index and mixing rate constant are investigated experimentally. The results show that a decrease in screw rotation speed and filling level results in an increase in the mixing rate. Faster mixing is observed with large particles, and the mixing rate constant of coarse particles is 1.5–2 times higher than that of fine particles. The particle size difference of materials puts the particles at a risk of segregation.     

Continuous quantitative monitoring of powder mixing dynamics by near-infrared spectroscopy

FT-NIR spectroscopy with a fiber optical reflection probe was applied as a process analytical technology tool for the continuous quantitative in-line monitoring of pharmaceutical powder mixing processes in a bladed mixer. Two powders, acetyl salicylic acid as an active pharmaceutical ingredient (API) and α-lactose monohydrate as an excipient were characterized in advance in terms of shear cell tests, flowability tests and particle-size determination to deduce flow properties of the powders. For the quantitative monitoring of the API content, two predictive models were developed with partial-least-squares calibration based on off-line calibration. On the basis of these predictive models, powder agitation and mixing times until blend uniformity were quantitatively monitored. Mixing experiments with systematically varied filling levels and filling protocols showed a strong variation in mixing, but eventually yielded uniform powder blend. Simulation results from the literature were linked to our experimental findings in order to identify and elucidate the effects of convective and diffusive mixing. In accordance to the international conference on harmonization acceptance level of 5% for the nominal API content, UV/Vis reference measurements were performed to verify the blend uniformity as predicted by the NIR measurements.     

均匀设计在煤矸石充填材料颗粒级配试验中的应用

多因素多水平采用均匀设计方法具有布点均匀、代表性好、使用方便等优点。作者采用U9（9^6）均匀设计方法对充填材料的颗粒级配确定进行了实验研究，确立了较优的颗粒组成，在此颗粒级配下，可使充填材料获得高的堆积密度和强度；在一定固相含量条件下，可使充填材料表观粘度明显降低．具有较好的工作性能。     

系统中组分混合水平对反应速率的影响

从物料的混合和混合水平的概念分析人手,探讨了反应物的混合水平对在不同反应器中物料反应速率的影响,推导得出不同型式反应器中在物料不同混合水平条件下的设计方程。