高效转子式选粉机的数值模拟的研究

设计高效转子式选粉机，利用ANSYS CFX11.0软件进行数值模拟研究高效转子式选粉机内部流场。发现转子转动条件下，转子附近分级区域的速度不是沿转子叶片均匀分布，其流场因转子的转动分成两部分：一部分进入转子，在转子内部形成巨大的涡，具有较小的切向速度。一部分与转子上部形成60°左右的夹角，与壁面之间形成一个涡，这两部分的流场形成双层强流场。通过对气固两相流运动模拟发现处于60 μm与100 μm之间颗粒部分通过转子区域。     

导流板形状对精细选粉机转速控制影响分析

生料终粉磨系统中的精细选粉机转速无法控制,严重影响了系统产量。通过流场仿真分析可以发现,卧式选粉机的入口气流一般高于设定的选粉机转子边缘速度。如果导流板设置不当,入口处的高速气流容易对转子起到推动作用,造成选粉机转速比给定的转速高,即转速失控,选粉过细,产量偏低。选粉机入口平面正上方的转子外围区域的流场对转子受到的转矩(大小和方向)影响很大。在设计导风叶片的结构时,应该考虑利用气流在该区域形成的、与转子转动方向相反的压差来对转子起到一定的阻碍作用,从而在不增加制动单元的情况下达到控制转速的效果。     

转笼式选粉机的流场模拟分析

利用美国ANSYS公司workbench环境下CFX软件对选粉机内部流场进行了模拟分析,结果直观地印证了选粉机的理论研究成果;文章还就选粉机转子内部有无涡流消除叶片模拟结果进行了分析比较,得出结论与理论相符.     

4.6m矿渣辊磨选粉机回转部分设计改进

正辊磨以其占地小、电耗低、噪音小、产量高、经济效益可观等优点越来越被建材行业所认可。4.6m矿渣辊磨是我公司主导产品,而选粉机回转部分是辊磨的核心部件,其传动系统通过变频调速电机带动减速机,减速机带动小带轮转动,通过皮带传动,带动大带轮和选粉机回转部分转动,且可以实现无级调速,从而保证提供不同的产品细度。选粉机回转部分主要由转子、大带轮、选粉机上下轴承、两个轴承座     

涡结构对对流传热影响的实验和模拟研究

利用计算流体动力学(CFD)模拟和粒子图像测速技术(PIV)实验相结合的方法研究了一个类似于板式换热器的模型在内部转子旋转的条件下,产生涡结构,提高传热效果的过程。首先采用PIV技术测定了在一定流量不同转速的条件下,模型中流场的变化。然后,运用CFD方法计算流动传热过程。计算的流场结构和PIV测定流场结构较为一致,显示出采用计算方法的可行性和有效性。计算结果表明,与没有转子转动相比,转子转动会使流场中出现涡结构,并且发生明显的扰乱。这优化了模型中流场结构,强化了换热效果。流动换热过程中,在压力损失的增加不变的条件下,换热效果得到了极大地提高。而且转速越快,换热效果提高越明显。     

选粉机三维动态流场数值研究

本文以TRM56.4辊磨选粉机为研究对象,构建三维实体模型,采用计算流体力学(Computational Fluid Dynamics,缩写CFD)的滑移动网格技术,解决了选粉机流场研究中转子转动过程数值研究技术难题,实现了选粉机三维动态流场的研究,结合流场计算结果分析了几种常见动叶片结构的阻力特性。     

4.6 m矿渣立磨选粉机轴承密封改进

<正>立磨以其占地小、电耗低、噪音小、产量高、经济效益可观等优点越来越被建材行业所认可。4.6 m矿渣立磨是我公司主导产品,而选粉机回转部分是立磨的核心部件,它的传动系统通过变频调速电机带动减速机,减速机带动小带轮转动,通过皮带传动,带动大带轮和选粉机回转部分转动,且可以实现无级调速,从而保证提供不同的产品细度。选粉机回转部分主要由转子、大带轮、选粉机上轴承、选粉机下轴承、轴承座(一)、轴承座(二)和三     

涡流空气选粉机分级性能的研究

利用计算流体力学CFD（Computational Fluid Dynamics）商用Fluent软件对涡流空气选粉机内部气固两相流动过程进行了数值模拟研究,采用三种方法（细粉收率法、Tromp曲线法及成品R-R粒度分布曲线法）对选粉机性能进行评价,并同实际标定结果进行比较,最后分析风量和转速对选粉机分级性能的影响.结果表明：模拟预测曲线与实践结果基本吻合,验证了CFD技术在涡流空气选粉机研究过程中提供信息的可靠性,为进一步拓展CFD技术在选粉机领域中应用提供佐证;转子转速对成品细度的影响远大于风量对成品细度的影响,同风量下,转速降低14.3％,成品中大于60μm粗颗粒增加3.42倍,同转速下,风量增加59.5％,成品中大于60μm粗颗粒增加17.9％.     

涡流空气选粉机分级性能模拟预测与实践结果的比较

利用计算流体力学CFD(Computational Fluid Dynamics)商用Fluent软件对涡流空气选粉机内部气固两相流动过程进行了数值模拟研究,采用三种方法(细粉收率法、Tromp曲线法及成品R-R粒度分布曲线法)对选粉机性能进行评价,并同实际标定结果进行比较,最后分析风量和转速对选粉机分级性能的影响。结果表明:(1)模拟预测曲线与实践结果基本吻合,验证了CFD技术在涡流空气选粉机研究过程中提供信息的可靠性,为进一步拓展CFD技术在选粉机领域中应用提供佐证;(2)转子转速对成品细度的影响远大于风量对成品细度的影响,同风量下转速降低14.3%,成品中大于60μm粗颗粒增加3.42倍,而同转速下风量增加59.5%,成品中大于60μm粗颗粒仅增加17.9%。     

改造选粉机提高磨机产质量

通过分析比较旋风式选粉机、转子式选粉机及高效选粉机的结构特点及分级原理，对旋风式选粉机进行技术改造；并通过实际生产数据对改造的情况作了简述。     

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.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

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.     

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.     

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。