金属烧结滤网在聚丙烯生产中的创新应用

通过将多层金属烧结网和金属烧结毡在聚丙烯生产上进行应用,来提升聚丙烯的产能。多层金属烧结网在挤出机组上的改良使挤出机组原更换滤网的时间由1～2天延长为7天更换,并通过对挤出机组过滤部件的改造,使挤出机组的过滤效率提升了1.6倍;金属烧结毡在聚丙烯原料的回收除尘应用使聚丙烯除尘滤筒维护时间由半年延长为2年。     

国内过滤介质调查（二）

笔者在“国内过滤介质调查(一)”中介绍了滤布及针刺毡,本文重点介绍编织滤网、滤带、各种板网、筛网、筛、滤纸、膜及烧结金属。 一、编织滤网、滤带 编织金属丝网是应用广泛、耐磨损的过滤介质,主要分编织金属丝网(带)与编织合成纤维网(带)两类。聚脂单丝滤带,是     

多层复合滤材结构完整性检测方法研究

通过试验证明,冒泡法试验不适用多层复合滤材结构完整性的评价。同时,利用复合滤材阻力等于单层滤材叠加的特性,提出了一种新评价方法,并通过试验证明,该方法是合理有效的。     

几种多孔金属材料的性能对比

测试了金属烧结纤维毡、五层不锈钢复合网的过滤性能,并通过与金属烧结粉末过滤材料对比,分析了其过滤性能与过滤精度的关系,结果表明,金属烧结纤维毡的过滤性能最好,烧结五层复合网、金属烧结粉末次之。再结合它们的一些其它性能,依次给出了它们不同的应用领域。     

大型储罐穹顶网壳结构研究综述

随着储罐的大型化,其穹顶网壳结构也在朝着大跨度、轻质量、薄厚度方向发展.穹顶网壳结构作为储罐的重要组成部分,其结构稳定性对于储罐安全性具有重要意义,国内外学者对大型网壳结构进行了大量研究工作.结合目前网壳结构的研究热点,总结了穹顶网壳结构选型、初始几何缺陷模拟、单层网壳结构稳定性、储罐穹顶施工受力分析等方面的研究现状,并对后续网壳结构研究工作提出了建议.     

建筑外墙防裂网对XPS燃烧行为及火灾危险性影响

为了探究建筑外墙防裂网与挤塑聚苯乙烯保温泡沫板(XPS)复合层的火灾危险性，揭示防裂网对XPS火灾性能影响规律，采用热重分析仪和锥型量热仪对XPS热解特性及三种典型防裂网复合层燃烧特性参数进行了系统测定，并分析计算各复合层火灾危险综合指数。研究表明，不同升温速率下，环境温度超350℃时XPS均处于不稳定状态，升温速率越小，热解越完全；抹灰钢丝和玄武岩纤维这两种材料的双层防裂网复合结构均促进了XPS的燃烧，而单层防裂网复合结构则降低了XPS的火灾危险性；玻璃纤维单层防裂网复合结构的火灾危险性高于双层防裂网复合结构，且玻璃纤维网复合结构增大了XPS的火灾危险性。因此，在复合保温板制作或外墙保温设计时可优先考虑单层玄武岩纤维网格布或单层抹灰钢丝网与XPS进行复合；尽可能避免使用玻璃纤维网格布与XPS进行复合，若无法避免，则可以考虑使用双层玻璃纤维网复合进而降低火灾危险性。研究结论填补了不同材料防裂网对XPS火灾危险性影响方面的不足，为建筑外墙保温面层及新型保温板复合材料的选择提供参考依据。     

法向载荷下含金属预埋件碳纤维层合板强度分析

建立了含圆柱形金属预埋件和阶梯形金属预埋件碳纤维/环氧树脂层合板的三维分析模型,单层板简化为三维正交各向异性材料。采用有限元方法对法向载荷下含金属预埋件四边简支层合板进行了应力分析,给出了发生初始损伤单层板各材料主方向应力分布和金属预埋件的VON MISES应力分布。基于复合材料单层板的最大应力强度准则给出了两种分析模型的极限载荷。分析结果表明,含圆柱形预埋件层合板初始损伤发生在45°铺层靠近孔边的2点钟方位,破坏模式为基体剪切破坏;含阶梯型预埋件层合板初始损伤发生在-45°铺层靠近孔边的10点钟方位,破坏模式为基体拉伸破坏。法向载荷作用下,阶梯型预埋件结构比圆柱形预埋件结构具有更大的传力面积,大部分纤维处于适宜的受拉状态,其极限载荷比圆柱形预埋件结构提高了40.36%。     

炻器产品快速烧成的研究

本文分析了用于炻器生产的原料化学成分、物理性能、工艺性能和烧结特性。进行了炻器产品单层快速烧成的实验研究，对试制品的各项性能进行了检测，并讨论分析了实验过程中的有关问题。该项工艺的推广有助于提高生产效率和节约能源。     

一种空气过滤装置

本实用新型提供一种空气过滤装置，该空气过滤装置从外至内依次包括前置过滤层、活性碳滤网层、滤膜层、光触媒层、紫外吸附层及后置过滤层，其中，该前置过滤层为一滤网层，由棉纱、无纺织布或直接由塑料构成，活性碳滤网层由含活性碳纤维构成，滤膜层包括纳米级的颗粒，光触媒层由纳米金粒子、纳米二氧化钛光触媒及碳纤维构成，紫外吸附层由纳米级的二氧化钛或锌的氧化物构成，后置过滤层由无纺织布或塑料构成。本实用新型的空气过滤装置不仅具有阻隔尘埃、清滤空气的功能，而且具有过滤空气中的病毒、细菌、粉尘微粒等微生物和吸附有毒气体的功效，对直径很小的病毒也有很好的防护作用。     

刚性烧结金属丝网的孔径计算

由于过滤介质材料、结构上的差异 ,过滤精度的确定多按国际标准 ASTMF 795(液固分离法 )。其测试手段较繁 ,且易受试验条件的影响。本文针对刚性烧结金属丝网采用高精密织机编制成形的微孔结构特点 ,提出了相应的孔径计算公式 ,其结果与实际过滤试验数据吻合。利用该式可有效计算单层平纹、斜纹滤网的有效孔径 ,可保证一定的过滤精度 ,同时该式对更高精度丝网的研制提供了理论依据。     

关于煤炭发热量表达形式的探讨

针对用户对煤炭发热量理解方面存在的问题 ,为了更科学地评价煤炭发热量 ,提出了标准态和生产态的概念 ,即标准收到基低位发热量、标准空气干燥基高位发热量、标准空气干燥基低位发热量和生产态收到基低位发热量 ,认为用标准收到基低位发热量Q0net,ar和生产态收到基低位发热量Q net,ar来评价煤炭质量比较合理。     

蛇形微通道内泄漏流特性

微流体系统通常具备极大的比表面积、易于控制等优势,在气-液相传质、传热、反应等方面具有良好的应用前景。本文考察了6个气液相体系在矩形截面蛇形微通道中的气液两相泰勒流流动情况以及气泡和液弹的动态行为,以气泡截面形状的几何模型为基础,得到了微通道中净泄漏流的量化方程。同时发现在较大的操作区间内,蛇形微通道对泄漏流的可控性优于直形微通道。并且详细分析了不同气液相流量、液相物性（表面张力和黏度）和气泡长度对蛇形微通道主通道净泄漏流的具体影响。     

Shock induced condensation in a fuel-rich oxygen containing bubble in a flammable liquid

Shock induced dynamics and explosion of a single oxygen containing bubble in liquid cyclohexane is calculated. The possibility, in principle, of fuel vapor condensation during bubble compression is shown. This condensation takes place, if the gas inside the bubble has a relatively high initial temperature or a low initial pressure. As a result of fuel vapor condensation the bubbles, which have an initial gas composition above the upper flammability limit, can, nevertheless, explode.It is shown that the fuel vapor condensation in fuel-rich bubbles is possible during compression stages of oscillations and during a few milliseconds after the end of bubble dynamics. The rate of the condensation process is estimated. According to estimations, this process is fast enough to significantly change the chemical composition of the bubble and shift it into the flammable range even during the compression stage of the first bubble oscillation.Explosion limits of a single bubble as a function of initial temperatures and pressures are calculated. It is shown that condensation processes extend the explosion range.The influence of a chemically inert gas (argon), on the bubble ignition threshold and parameters of bubble explosion is analyzed. It is shown that argon addition in a bubble can reduce the ignition threshold and therefore increase the explosion hazard. On the other hand, such additions reduce explosion pressure and can be used for mitigation of explosions in bubbly liquids.     

幂律流体中平行上升双气泡间相互作用研究

采用流体体积(VOF)法对非牛顿幂律流体中平行上升双气泡间相互作用进行了模拟研究.结果表明:剪切变稀效应及气泡周围流场结构对气泡间相互作用的贡献分别随着气泡间距增大而减小,气泡间相互作用主要受气泡间流体涡旋结构控制.当初始间距很小时,气泡平行聚并发生;随着初始间距增大,双气泡行为转变为相互影响的平行上升;当初始间距增大...     

Single bubble formation in high pressure liquid—solid suspensions

Bubble formation from a single nozzle is investigated analytically and experimentally in nonaqueous liquid and liquid—solid suspensions at pressures up to 17.3 MPa. A mechanistic model is proposed to predict the initial bubble size in liquid—solid suspensions, by taking into account the various forces affecting the bubble growth including those induced by the presence of the particles, such as the suspension inertial force and the particle-bubble collision force. It is found that the initial bubble size in the suspensions is generally larger than that in the liquid mainly due to the inertia effect of the suspension. The initial bubble size increases with the solids holdup. The pressure has an insignificant effect on the initial bubble size in both the liquid and liquid—solid suspensions under the conditions of this study. The model can reasonably predict the initial bubble sizes obtained in this study and those reported in the literature.     

对净现值分析法认知的几个问题

介绍了净现值的概念、计算方法、净现值分析的时间可比,以及现金流对净现值计算的影响,提出净现值分析法用于一些不确定条件下的决策分析有独特的长处,对于任何项目(合功能替代和不合功能替代)都可用净现值法直接进行比较,且在净现值计算时要以全投资现金流为依据,这样计算出的结果才是有意义的、可靠的。     

A net draft tube slurry airlift bioreactor for 2,4‐D (2,4‐dichlorophenoxyacetic acid) pesticide biodegradation

Biodegradation of the pesticides 2,4‐D have been investigated in a net draft tube airlift bioreactor at different concentrations (10–160 ppm) and air flow rates (0.75–4 L min^?1), employing acclimatised activated sludge. A modification for the glass draft tube airlift bioreactor was proposed in which the draft tube is made of non‐woven polypropylene textile net. The experiments were carried out as well in a bubble column (BC) for comparison. The results confirmed that immobilising the activated sludge on the net of the draft tube could enhance the substrates mass transfers and improve the biodegradation rate. A mathematical model was developed to simulate the biodegradation process. The simulated results were in good agreement with the experiments.     

单个运动气泡近界面浓度场的研究

对单个气泡传质的近界面浓度场影响因素进行了实验和理论研究．实时激光全息干涉法测量结果表明,运动气泡近界面浓度是一个定态值,受流速、泡径、温度等因素影响显著;假设该传质过程达到局部平衡,进行热力学分析,得到的结论与实验结果一致．在实验测量结果的基础上,对单个O_2气泡在乙醇中吸收时的传质近界面浓度场进行了数值模拟,取得了良好的结果．     

单气泡沿倾斜绝热表面运动特性的LBM方法研究

气泡沿斜面运动现象在工业生产中广泛存在,采用格子Boltzmann方法(LBM)研究单个气泡沿倾斜绝热表面的运动过程,考察气泡的初始直径、斜面倾角、Eotvos数(Eo)对气泡的变形和气泡形心与斜面垂直距离的影响,探讨相同初始直径的气泡沿斜面运动的稳定终态速度与倾角和Eo之间的关系。通过模拟得出气泡沿斜面的运动规律:斜面倾角越大,气泡前后端不对称性越大;气泡在上升过程中,形心轨迹与斜面保持平行;当倾角大于45°时,形心与斜面的垂直距离和Eo变化一致,当小于45°时,变化相反;相同初始直径气泡的稳定终态速度随倾角和Eo的增加而增加。     

Preparation of near net size porous alumina-calcium aluminate ceramics by gelcasting-pore-forming agent processs

In the processing of porous ceramics, shrinkage from green body to sintered compact during drying and sintering is one of the key concerns which affect microstructure and properties of porous ceramics. Through releasing gases from the burning of the pore forming agents, and volume expansion from the formation of low density resultants during sintering, the sintering shrinkage can be effectively compensated and near net size preparation can be achieved. Herein, near net size porous alumina-calcium aluminate ceramics with controllable shrinkage have been prepared using a combination of gelcasting and pore-forming agent process by adjusting the amount of CaCO₃ and polymethyl methacrylate (PMMA) microspheres added. Al₂O₃ and CaCO₃ were used as raw materials, PMMA microspheres were used as pore-forming agent, isobutylene/maleic anhydride copolymer (Isobam104) was used as gelling agent and dispersing agent. The effects of the addition amounts of CaCO₃ and PMMA in the slurry on the phase composition, shrinkage, porosity, and strength of porous alumina-calcium aluminate ceramics were investigated. The results show that as the CaCO₃ addition amount increases from 0 to 20 wt%, the shrinkage of the samples gradually decreases from 7.3% to −1.4%, and the consequent porosity increases from 58% to 66%, while the compressive strength increases from 5.9 to 15.5 MPa. When PMMA content increases from 10 to 50 wt%, the shrinkage of the samples decreases first and then increases, the porosity increases from 51% to 74%, and the compressive strength decreases from 12.5 to 5.3 MPa. The mechanisms for controlling shrinkages during preparation of porous alumina-calcium aluminate ceramics can be attributed to the following aspects: on one hand, gas release from burning of PMMA and decomposition of CaCO₃ during sintering; on the other hand, volume expansion due to the formation of lower density calcium aluminates which come from the reactions between CaO and Al₂O₃. The near net size preparation technique is of great significance for the manufacture of porous ceramics since the subsequent machining cost can be effectively reduced.