双辊薄带铸轧熔池内流场和温度场数值模拟

以带宽1000 mm,辊径600 mm的双辊薄带铸轧过程为研究对象,基于Fluent软件,建立了薄带铸轧熔池三维有限体积模型,对其中钢液流动状态及传热进行数值模拟,并考察了新型浇铸系统结构、布流器开孔倾角、铸轧速度、过热度及冷却强度对铸轧AISI304不锈钢熔池的流场和温度场的影响.结果表明,采用浸入式水口,多孔布流器,导流坝以及分流体组合的新型浇铸系统,且水口浸入布流器熔池内,布流孔向上倾角15o~18o,铸带速度在60~80m/min,熔池自由液面湍流动能最大值为0.0175 J/kg,熔池表面温差低于20 K,钢液与铸轧辊接触面能稳定形成大于0.6 mm的凝固坯壳.     

基于CAE分析的压铸镁合金、铝合金模具温度场比较

用数值模拟的方法，计算并对比分析了浇注温度和模具预热温度对镁合金、铝合金压铸件及压铸模具温度场的影响，得出了压铸镁合金模具温度场的分布特征。     

数值模拟方法在橡胶冷流道设计中的应用研究

将数值模拟方法与正交试验方法相结合,对橡胶注射模具冷流道浇注系统的温度场进行数值分析和研究。数值计算采用隐式定常求解,用k-ε湍流模型封闭运动方程,近壁区的流动采用标准的壁面函数法,固体壁面用无滑移边界条件,压力-速度耦合用SIMPLE算法。试验设计采用三水平三因子的正交试验法,得出不同水平组合下的温度场分布,导热油油路直径为10 mm、导热油入口温度为95℃、导热油入口流速为3.5 m·s-1时,胶料温度最佳,温度分布均匀。     

数值模拟技术在橡胶冷流道设计中的应用研究

将数值模拟技术与正交试验方法相结合,对橡胶注射模具冷流道浇注系统的温度场进行了数值分析及研究。数值计算采用隐式定常求解,用k-ε湍流模型封闭运动方程,近壁区的流动采用标准的壁面函数法,固体壁面用无滑移边界条件,压力—速度耦合用SIMPLE算法。试验设计采用三水平三因素的正交试验法,得出三个不同水平的导热油油路直径、导热油的入口温度以及入口速度温度场分布,经过统计计算获得最佳结果：导热油油路直径为10mm、导热油的入口温度为95℃、流动速率为3.5m/s。     

基于交替方向隐式差分算法的连铸坯凝固传热模型

针对连铸板坯的凝固传热问题,考虑板坯形状规则的特点,基于交替方向隐式差分算法建立沿连铸板坯宽度和厚度方向的二维凝固传热模型.该模型可以模拟铸坯液相区和两相区的变化、铸坯坯壳厚度变化及铸坯凝固末端的位置等参量,可实现对铸坯温度场分布特征的计算跟踪.以某炼钢厂立弯式板坯连铸机为研究对象进行工业测试,铸坯断面尺寸为1082 mm×200 mm,铸机拉速为1.3 m/mm,钢种为Stb32z条件下的模拟计算和实测结果表明,凝固传热模型的计算效率可以满足生产要求,计算结果符合凝固规律,计算温度与便携式红外测温仪的实测温度误差为1.4%.     

基于CFD的流延膜冷却效率研究

以平行流道流延辊为研究对象,利用计算流体动力学软件对流延膜在流延辊上的冷却过程进行数值模拟,得到了不同流延膜厚度和流延辊转速条件下流延膜的温度场。结果表明,流延膜温度分布为中间高两端低,且靠近冷却水入口一侧的温度低于另外一侧。流延膜的冷却速率随流延膜厚度的增加而降低,流延膜的冷却效率和宽度方向上的温度分布均匀性随流延膜厚度的减小而提高。流延膜的冷却速率随流延辊转速的升高而降低,流延膜的冷却效率和宽度方向上温度分布的均匀性随流延辊转速的降低而提高。     

电极插入深度对矿热炉加热影响的CFD分析

为了探究三相交流电矿热炉在稳定工作时的炉内工作情况,建立了48MW矿热炉的三维有限元模型,研究了不同电极插入深度对于炉内温度场分布的影响,并对熔池内的融化凝固情况进行了分析。结果表明：熔池内最高温度在电极下方的坩埚区内;固液两相的分布情况与温度场梯度变化有关;随着电极插入深度的增加,熔池内部的最高温度会不断降低。     

铁浴反应器流场及温度场的数值模拟

以铁浴熔融还原工艺的铁浴反应器为研究对象,基于FLUENT软件,对反应器内流场及温度场进行了数值模拟,考察了侧吹和顶吹操作条件对铁浴熔池均混时间、铁浴上部空间气相组成及温度分布以及煤气二次燃烧率的影响.计算结果表明,铁浴熔池均混时间随侧吹喷枪倾角及插入熔池深度的增加均呈现先减小后增大的趋势.在本计算条件下,当侧吹倾角为50°,侧吹喷枪插入深度为0.3 m时,可获得最短的熔池均混时间.铁浴反应器上部空间煤气二次燃烧率随顶部热风喷枪的升高而增大,项枪距熔池液面距离每增加0.2 m,上部空间煤气二次燃烧率可提高约1.1%;随顶枪位置上移,氧气分布范围扩大,气体环流区也随之上移.     

一种螺旋流道辊的数值模拟及结构优化

对已有的螺旋流道辊模型进行合理简化,运用流场仿真软件Fluent对流道辊的温度场进行了仿真分析,得到了流道辊的温度场,从而得到了流道辊内流体速率、流体温度场、辊筒表面温度场等。通过分析模拟仿真结果,得到了辊筒外表面温度不均匀的原因,并在此基础上,以提高辊筒外表面的温度分布均匀性为目标,对流道结构进行多次改进,找出一种最佳方案,明显改善了辊筒端部的温度分布均匀性,使辊面的有效利用长度延长了约50 mm。     

大方钢坯连铸二冷区传热与凝固过程数值模拟

采用改进的波动冷却法(FCA-I)对大方坯连铸二冷区传热与凝固过程进行数值模拟,并与单调冷却法、波动冷却法(FCA)的计算结果进行比较. 结果表明,3种方法计算所得铸坯矫直前温度及液芯长度均与实测值相近,但FCA-I法计算结果更准确,可实时预测拉速变化时铸坯表面温度分布与液芯长度变化. FCA-I法既保留FCA法能准确反映铸坯足辊间温度、凝固壳厚度变化的优点,同时也克服了其难以适应变拉速的缺点. FCA-I法模拟所得结晶器内和二冷区凝固壳厚度dshell与凝固时间t的关系分别满足dshell=19.62t1/2-2.52和dshell=29t1/2,模拟值与文献结果基本一致.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料，介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比，介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序，对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

Inorganic/organic nanocomposite coatings: The next step in coating performance

Inorganic/organic hybrid materials have considerable promise and are beginning to become a major area of research for many coating usages, including abrasion and corrosion resistance. Our primary approach is to prepare the inorganic phase in situ within the film formation process of the organic phase. The inorganic phase is introduced via sol-gel chemistry into a thermosetting organic phase. By this method, the size, periodicity, spatial positioning, and density of the inorganic phase can be controlled. An important aspect of the inorganic/organic hybrid materials is the coupling agent. The initial task of the coupling agent is to provide uniform mixing of the oligomeric organic phase with the sol-gel precursors, which are otherwise immiscible. UV-curable inorganic/organic hybrid systems have the advantages of a rapid cure and the ability to be used on heat sensitive substrates such as molded plastics. Also, it is possible to have better control of the growth of the inorganic phase using UV curing. It is our ultimate goal to completely separate the curing of inorganic and organic phases to gain complete control over the morphology, and hence optimization of “all” the coating properties. Thus far, it has been found that concomitant UV curing of the inorganic and organic phases using titanium sol-gel precursors afforded nanocomposite coatings which completely block the substrate from UV light while maintaining a transparent to visible light. Also, it has been found that the morphology of the inorganic phase is highly dependent on the concentration and reactivity of the coupling agent. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004, in Chicago, IL.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Some Large Wood-Boring Beetles in Southeastern USA

Ethanol and α-pinene were tested as attractants for large wood-boring pine beetles in Alabama, Florida, Georgia, North Carolina, and South Carolina in 2002–2004. Multiple-funnel traps baited with (−)-α-pinene (released at about 2 g/d at 25–28°C) were attractive to the following Cerambycidae: Acanthocinus nodosus, A. obsoletus, Arhopalus rusticus nubilus, Asemum striatum, Monochamus titillator, Prionus pocularis, Xylotrechus integer, and X. sagittatus sagittatus. Buprestis lineata (Buprestidae), Alaus myops (Elateridae), and Hylobius pales and Pachylobius picivorus (Curculionidae) were also attracted to traps baited with (−)-α-pinene. In many locations, ethanol synergized attraction of the cerambycids Acanthocinus nodosus, A. obsoletus, Arhopalus r. nubilus, Monochamus titillator, and Xylotrechus s. sagittatus (but not Asemum striatum, Prionus pocularis, or Xylotrechus integer) to traps baited with (−)-α-pinene. Similarly, attraction of Alaus myops, Hylobius pales, and Pachylobius picivorus (but not Buprestis lineata) to traps baited with (−)-α-pinene was synergized by ethanol. These results provide support for the use of traps baited with ethanol and (−)-α-pinene to detect and monitor common large wood-boring beetles from the southeastern region of the USA at ports-of-entry in other countries, as well as forested areas in the USA.