水平管道中LNG饱和流动沸腾两相传热

对水平LNG输送管道的LNG饱和流动沸腾传热现象进行数值研究。管道内部光滑,内径为8 mm。分别计算了管道入口压力从0.3到0.7 MPa、热流量范围为8~36 k W/m2、质量流量范围为49.2~201.8 kg/m2s。基于混合模型对所设计的几组工况进行数值计算。得出了蒸汽质量、入口压力、热流量和质量流量对传热热性的影响。结果表明:热流量显著影响着LNG的局部传热系数。随着热通量的增高,局部传热系数也变大。当质量流量较高时,局部传热系数受强制对流的影响较大。传热系数随着进口压力的增加而增大。当质量流量变高时,入口压力越大局部传热系数越低,随着进口压力的增大,进口压力对传热的影响在逐渐减弱。     

基体条件对等离子喷涂Sm_2Zr_2O_7热障涂层热冲击性能的影响

采用有限元分析软件ANSYS对等离子喷涂Sm2Zr2O7热障涂层在金属基体材质类型、厚度、半径变化时涂层的冲击热应力进行了分析。结果表明,涂层表面及表面层/金属粘结层界面处热应力及其应力梯度随着金属基体热膨胀系数增加而增大。当基体厚度超过20mm后,其对冲击热应力的影响基本可以忽略。当基体半径达到28mm后,涂层最大径向冲击热应力趋于稳定,最大轴向热应力随基体半径增加逐渐减小,最大剪切应力不受基体半径的影响。     

气液固三相流化床局部相含率

在以焦末为固相、空气为气相、水为液相的三相流化床中研究了局部气含率和局部固含率径向分布。实验用流化床内径100 mm,高1.7 m,焦末粒度1.07 mm。分别采用电导探针法和光纤法测定局部气含率和局部固含率。结果表明:表观气速为0.35—0.71 cm/s,表观液速为2.12—3.54 cm/s时,局部气含率在流化床中沿径向r/R=0—0.8处分布较均匀,在靠壁面处下降至约0.5%,且随表观液速增加而减小,随表观气速增加而增大,且在距分布板轴向高度分别为370 mm和470 mm时趋势一致,大小沿轴向增加,在表观气速一定时,液速小于2.12 cm/s时,气含率沿径向减小的趋势较明显。局部固含率沿径向分布较均匀,基本不随表观气速变化而变化,随表观液速增大而增大,且在距分布板轴向高度分别为370 mm和470 mm时趋势一致,大小沿轴向减小。     

单层厚度对Sm2Zr2O7/8YSZ热障涂层残余热应力的影响

采用有限单元法研究了金属粘结层厚度、热生长氧化层厚度及陶瓷层厚度对Sm2Zr2O7/8YSZ双陶瓷层热障涂层残余热应力的影响。结果表明,金属粘结层厚度为0.1mm时,涂层径向应力最小。涂层径向应力随热生长氧化层的厚度的增加而减小。当YSZ厚度在0.1～0.5mm之间时,径向热应力随YSZ厚度增加而增大,超过0.5mm后应力基本不再变化。陶瓷层最佳厚度组合是0.1mmYSZ+0.9mmSm2Zr2O7。     

微纳米气泡的特性表征研究

为进一步探究微纳米气泡发生系统的性能。基于喷射法原理,研究文丘里管内径、气泡发生器孔径和级数等因素对微纳米气泡粒径分布的影响。经实验测试,结果表明：当文丘里管内径由2.7 mm增至2.9 mm,气泡粒径随内径增加呈先减小后增大趋势,即气泡的平均粒径由10.88μm先减小至3.069μm,后增大至7.997μm;当气泡发生器孔径从0.7 mm增加至0.9 mm,气泡粒径随孔径增加呈递减趋势,即气泡的平均粒径由4.106μm减至2.954μm;当级数由1增至3级时,气泡粒径随级数增加基本保持一致。     

多孔介质内复合对流传热传质的数值分析

采用数值方法分析了具有非均匀内热源的竖直套管中复合对流传热传质,考查内热源分布系数M和热质二浮力比N对速度、温度、浓度分布以及Nusselt数和Sherwood数的影响。结果表明：当N〉1时速度V为正,其值随N的增加而增大;当N〈-1.5时,V则先负后正。随着M增大,等温线和等浓度线分布更加密集,传热和传质过程更加明显。     

岩石三轴压缩端部效应及受力变形状态数值模拟

为研究端部效应对岩石三轴压缩过程中受力和变形的影响,应用ABAQUS对岩石三轴压缩试验进行模拟,分析岩石外、内部应力应变云图的演化及不同路径上各单元的应力应变。结果表明：（1）在端部摩擦作用下,试件端部附近的应力、应变分布较为复杂。（2）弹性阶段靠近上下端部约13mm范围内受端部效应影响,轴向应力较小,径向应力较大,径向应变较小;中间约24mm范围内受端部影响较小,轴向、径向受力和变形较为均匀。（3）靠近端部的水平路径上,两侧的径向应力、应变较大,中部较小;位于中部的水平路径上径向应力、应变分布较为均匀。（4）在弹性阶段,位于试件中下部水平路径上各单元应变均匀增大;在破坏阶段,穿过应变局部化带单元应变快速增加,应力有所减小,发生应力转移,其余单元应变减小,发生变形回弹现象。     

有压腔式吸热器内辐射传播过程的Monte Carlo模拟

建立了有压腔式吸热器的光学模型，采用Monte Carlo光线追迹法（MCRT）对吸热器中太阳辐射传播、吸收过程进行了模拟研究。在光线追迹计算中，将非连续多孔结构吸热体中的光线传播过程近似为各向同性均匀连续浑浊介质中的传播过程，并对多孔结构吸热体区域内网格做了局部加密处理，采用非均匀网格统计各个网格吸收的光子能量权值之和，从而在较低计算资源消耗的前提下实现了大尺度非规则多孔结构吸热体内的热流分布计算。计算结果表明，在给定工况条件下多孔结构吸热体所吸收的太阳辐射热流集中于吸热体的顶部区域，局部热通量极值达到了2.87×10⁹W·m^-3，而在吸热体的两侧，热通量迅速减小，整个吸热体内的太阳辐射热流分布呈现出极不均匀的特征，从而影响吸热器系统运行的稳定性和安全性。     

轴向非均匀热流下熔盐吸热管的传热特性

以熔盐为传热工质,对轴向非均匀热流下吸热管内传热进行了数值模拟。结果表明:吸热管顺流和逆流加热时,吸热管内高热流侧流速均大于对应位置的低热流侧流速,轴向热流突变处的管内流速变化率较大。吸热管逆流加热的管外壁最高温度及高温区平均温度明显低于顺流加热,逆流加热的管壁的热应力大大减小,高温区的辐射热损失也减小。     

低压蒸汽环境中水蒸发界面温度和蒸发速率的实验研究

蒸发相变广泛存在于薄膜过程及晶体生长等工业生产和日常生活中,液层表面蒸发和热毛细对流相互影响、相互制约,使得蒸发界面能量传递机制变得非常复杂。为了深入了解水在低压纯蒸汽环境中的蒸发特性,对环形液池内水蒸发时的温度分布和蒸发速率进行了一系列实验研究。环形液池壁温控制在3~15℃之间,蒸发环境压力在394~1467 Pa之间变化,开始测量时液层深度为10 mm。结果表明,蒸发界面气相侧温度总是高于液相侧,气液界面存在明显的温度跳跃。随着压比减小,蒸发速率增加,界面温度跳跃随之增大;随着距壁面距离增加,局部蒸发速率降低,温度跳跃值减小;相同压比下,随着壁面温度的升高,气相侧热通量减小,蒸发界面温度跳跃值整体降低;在实验范围内测得的最大温度跳跃值为2.56℃。由于蒸发冷却效应和热毛细对流的耦合作用,蒸发界面下液相侧存在一个厚度为2 mm左右的温度均匀层,且壁面附近温度均匀层厚度大于中间区域厚度。在温度均匀层内,径向温度梯度诱导的热毛细对流将热量从壁面传输至气液界面以补偿蒸发所需汽化潜热;在温度均匀层以下,浮力对流和导热共同作用使得液相温度迅速升高。     

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.