模拟化工大气环境中不同类型铜管的腐蚀研究

在自制的实验箱中模拟化工大气环境,考察了裸铜管、化学镀標铜管和化学镀操-染黑铜管的腐蚀情况,并利用扫描电镜和三维形貌仪观察了不同类型铜管腐蚀前后的微观组织及腐蚀后的局部三维形貌。结果表明:在模拟化工大气环境中腐蚀后裸铜管表面存在连成片且很深的蚀坑,化学镀襟铜管表面的胞状物消失,化学镀鎳-染黑铜管表面存在沿着缝隙分布的大面积细小蚀坑;化学镀铢铜管的耐蚀性最好,其次是化学镀操-染黑铜管,裸铜管的耐蚀性最差。     

中空FRP踏板

日本宇部日东化成公司靠自己的拉拔成型技术(热塑性树脂被覆拉拔成型法)开发了新的FRP制品.与普通的拉拔成型相比,热塑性树脂包覆代替了金属模.由于消除了硬质金属模产生的拉拔阻力,能高速生产,便于制造小孔径的FRP制品.另外还具有可进行包覆的异形加工,对未硬化的绳股还可加工成绳和网等.此复合管是以ABS树脂管为芯并设有FRP层和表面包裹树脂层等三层结构的FRP管.三层都牢固地粘结在一起,具有重量轻、强度高、刚性好等特征.     

顶驱钻井旋转控制头驱动器研究

在顶驱装置驱动旋转钻具的情况下,旋转控制头胶芯无法随钻柱一起同步旋转,这样造成胶芯胶芯磨损严重,使用寿命大幅降低。本文通过设计顶驱钻井旋转控制头驱动器,可以给旋转控制头提供驱动力,使得旋转控制头胶芯与钻杆同步转动,减小胶芯磨损,提高旋转控制头使用寿命,降低钻井安全隐患。     

燃烧器芯数对CVD熔石英玻璃性能的影响

本文通过数值模拟研究了燃烧器芯数对CVD熔石英玻璃性能的影响,讨论了采用五芯、七芯和九芯三种结构燃烧器时沉积面上的温度、OH^-浓度及SiO₂浓度分布,并分析了不同氢氧当量比的影响规律。结果表明:相比于五芯结构燃烧器和七芯结构燃烧器,采用九芯结构燃烧器可以在沉积面获得更加均匀的SiO₂浓度分布和温度分布;当使用九芯燃烧器时,氢氧当量比为1.5可以提高沉积面上温度、OH^-浓度和SiO₂浓度的分布均匀性,从而有利于提高熔石英玻璃的折射率均匀性。     

反光膜微结构阵列电铸电流密度分析

为了获得高质量的微结构阵列反光膜产品,控制电铸过程尤为重要。芯模所在阴极表面的电流密度分布直接影响电沉积层的质量。对不同形状的芯模和不同极板间距的微棱结构电铸系统,利用有限元方法分析了阴极表面的电流密度。结果表明:极板间距直接影响电流密度分布,计算值与测试结果吻合;芯模棱锥顶角发生变化,该位置处的电流密度变化不大;芯模棱锥深宽比对电流密度分布影响很大;当棱锥侧面与基板夹角为锐角时,凹槽处很难电铸。实际微棱电铸结果说明了仿真的可靠性。     

三种铜材管束的关键制造技术

通过多种不同材料铜管管束的制造技术分析,指出设计时材料质量指标及检测要求必须明确,铜材管束的配合尺寸精度要高,制造工艺要照顾到各所选铜材的各种冷热加工特性,宜在专门的洁净厂房内制造,预防表面损伤变形。还指出了管头连接的关键工艺及注意事项,选择多胀珠胀管器或橡胶胀接铜管头的优点是橡胶与铜之间的摩擦系数小,胀后橡胶易回弹,不易损伤铜管内表面。     

钢塑复合异型材共挤流道内熔体流动特性的数值模拟

结合钢塑复合共挤工艺特点,建立了复合共挤出流动的数学模型。采用有限元分析软件Ansys对钢塑复合中空异型材共挤流道内熔体的三维等温非牛顿流动进行了数值模拟;讨论了内部芯材以不同速率移动时,流道内熔体压力、速度和粘度的分布特点及变化规律,并与普通异型材挤出进行了对比。结果表明:随着芯材移动速率的提高,流道内压降减小;在熔体与芯材接触结合区域,压力和速度梯度明显增加,粘度减小,易出现不稳定流动;流道内熔体有较高的轴向速率,径向速率对称分布,其流动特征为典型的收敛流动;由于芯材在牵动,熔体最大流速出现在口模成型段,即挤出熔体与芯材的会合处。     

基于CAE的夹芯注射成型物料配比与层间界面优化

以高密度聚乙烯(HDPE)为夹芯注射成型工艺的壳层物料、低密度聚乙烯(LDPE)为芯层物料,在工艺参数固定的前提下,基于CAE研究了不同物料配比时最终塑件的芯、壳层树脂界面分布情况。研究表明,壳层物料增多,越不易发生芯层物料裸露现象,且层间界面越向中心位置靠拢;对于本实验,在工艺参数固定的情况下,壳层、芯层物料配比为66∶34时,层间界面分布情况较为合理;基于CAE,可以快速且直观的分析夹芯注射成型工艺的层间界面分布情况,从而恰当的调整原材料配比。     

气辅共注射成型工艺的实验研究

通过对现有注塑、气辅设备的改造,时气辅共注射成型工艺进行了实验研究。考察了材料流变性能、注射量和气体注射延迟时间对材料层厚分布及气体在熔体中穿透的影响规律。实验表明,芯皮层材料层厚分布主要受芯皮层熔体粘度比和芯皮层注射量的影响;气体在熔体中的穿透主要受熔体的总注射量和注气延迟时间的影响。     

三锥体旋流芯管能量损失分析

应用ANSYS流体力学计算软件模拟了旋流芯管内流体压力损失的分布,分析了流体速度在旋流芯管内各段的变化情况,得到了能量损失在旋流芯管各段的分布规律。在此基础上分析了旋流芯管各段引起能量损失的主要因素,证明了能量损失主要发生在进口管段和尾管段。     

Analytical expressions for transient melting of polymer pellet sliding against adiabatic wall

The melting of polymer caused by friction before the solid plug is formed is an important phenomenon in the plastic injection process. To analyze the melting process caused by solid particles sliding against the bellow, a method that can simulate behavior of each particle during the calculation should be used. Particle element numerical method is hence adopted in the analysis for this research to take into consideration the behavior of each particle, where the melting of pellets caused by friction against flight and screw are assumed as friction against adiabatic walls. In this paper, analytical expressions of the transient melting process for spherical polymer pellets sliding against adiabatic wall are derived, which is essential for the numerical simulation of melting process in solid conveying section by particle element method.     

煤粉锅炉炉膛燃烧一维数学模型的研究

为了有效地进行直流煤粉多相流动与燃烧数值模拟,实现煤粉低NOx燃烧,本文在连续介质模型的框架中建立了综合考虑气—固两相流流动、燃烧与传热的直流煤粉燃烧一维数学模型。应用这一模型对一维煤粉炉炉膛内煤粉燃烧和气体燃烧的数值计算表明,该模型可快速有效地用于模拟直流煤粉多相流动与燃烧过程,给出炉内温度、NOx分布等主要参数。     

基于分离效率的卧螺离心机CFD分析

从分离效率的角度对卧式螺旋卸料离心机转鼓内的流场进行数值分析.通过剖析推料螺旋与转鼓溢流堰的结构特点可知,转鼓内流体在轴向为薄层流动,在径向由于涡流产生向内流动导致颗粒上浮,这两者对离心机分离效率有决定性的影响.结合CFD数值分析和颗粒的Stokes沉降运动关系,提出将薄层流动与上浮临界粒度应用于离心机分离能力计算的理论和方法.文章通过定义沉降粒度和上浮临界粒度,进一步把分离能力计算与分离效率相关联,使该方法更接近离心机分离工艺的实际情况.通过对工业中典型离心机进行实例计算,证明了该方法的可行性和准确性.     

Numerical computation of the fiber diameter of melt blown nonwovens produced by the inset die

Melt blowing is used commercially as a one‐step process for converting polymer resin directly into a nonwoven mat of microfibers. The inset die is often used to produce polymeric fibers in the melt blowing process. The air jet flow field model for the dual slot inset die is established. The flow field model is solved by using the finite difference method. The numerical computation results of the air velocity distribution coincide with the experimental data. Then the air drawing model of polymers in the melt blowing process established in our previous research is solved with the aid of simulation results of the air jet flow field. The final fiber diameter of the nonwoven fabrics predicted by the air drawing model of polymers tallies with the experimental data. The results show the great potential of this research for the computer assisted design of melt blowing technology and equipment. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

一种塑料拉伸疲劳寿命的测试方法

利用损伤力学方法对高分子材料的疲劳破坏过程进行研究,并使用VisualBasic语言进行编程,可通过此程序对疲劳过程进行计算并输出图线。这种基于高周疲劳损伤模型的数值模拟方法只要通过简单的拉伸实验得到材料的物性参数并将其带入此模型,即可对材料产生疲劳裂纹之前的损伤情况进行模拟并对可其失效寿命进行预测,节约了大量的时间和资金。     

3-D Simulation of Electroosmotic Injection and Migration in Microchannels: Effects of Non-Rectangular Cross Section

A numerical study of the 3-D characteristics of electroosmotic injection and migration of sample species in microchip capillary electrophoresis systems is reported. In particular, the effect of a non-rectangular cross section commonly found in isotropically-etched microchannels is thoroughly investigated through 3-D numerical simulations. A non-rectangular cross section resulted in a vertically non-uniform sample plug during the loading stage. Conventional 2-D simulation approach can result in up to 40% errors in the calculation of injection qualities. It was also found that the 2-D simulation using a proper channel width has a good agreement with the 3-D simulation data.     

Three‐dimensional simulation of thermoforming process and its comparison with experiments

Three‐dimensional solid element analysis and the membrane approximated analysis employing the hyperelastic material model have been developed for the simulation of the thermoforming process. For the free inflation test of a rectangular sheet, these two analyses showed the same behavior when the sheet thickness was thin, and they deviated more and more as the sheet thickness increased. In this research, we made a guideline for the accuracy range of sheet thickness for the membrane analysis to be applied. The simulations were performed for both vacuum forming and the plug‐assisted forming process. To compare the simulation results with experiments, laboratory scale thermoforming experiments were performed with acrylonitrile‐butadiene‐styrene (ABS). The material parameters of the hyperelastic model were obtained by uni‐directional hot tensile tests, and the thickness distributions obtained from experiments corresponded well with the numerical results. Non‐isothermal analysis that took into account the sheet, temperature distribution measured directly from the experiments was also performed. It was found that the non‐isothermal analysis greatly improved the predictability of the numerical simulation, and it is important to take into account the sheet temperature distribution for a more reliable simulation of the thermoforming process.     

低温阀门闸板应力场的数值计算及分析

在对低温闸板结构进行简化后,采用有限元法开发了应力分析软件,对应力、位移场进行了数值模拟,并绘制了应力等值线图、位移图和应力变化曲线图,探讨了应力与变形的规律,为进一步完善低温闸板的设计提供了理论依据。     

低温投产过程中罐内原油温度变化规律研究

建立了5×10~4m~3浮顶油罐低温投产过程的数值计算模型,利用Fluent计算流体动力学软件,对不同工况下原油的流动及传热过程进行数值模拟。计算得到不同工况下罐内原油的温度变化规律,为制定浮顶油罐低温投产运行方案提供理论依据。     

高落差粉尘扩散规律和分布特征

高溜井放矿过程中会形成强大的冲击气流引起粉尘扩散,造成严重的井下环境污染,对其进行有效治理一直是井下通风除尘的工作重心,本工作利用相似实验和数值模拟相结合的方式探究溜井放矿过程中粉尘的扩散规律和分布特征。通过改变放矿质量、矿石粒径、溜井密闭程度、含水率等因素测试不同条件下气流大小和粉尘浓度分布,并利用CFD-DPM耦合方法模拟卸矿过程中的气?固两相流,研究气流和粉尘浓度时空分布特征。结果表明,最大粉尘浓度和风速随放矿质量增加而上升,随颗粒粒径和溜井密闭程度增大而降低,且含水率越大,粉尘浓度越小,风速无明显变化,在放矿过程中矿石颗粒之间碰撞占主导作用,颗粒流呈横向分布。