Preparation and Properties of Rare Earth Modified Carbon Black/Natural Rubber Composites

The oxides Eu, Ho, Er and Dy were used to prepare the hydroxides of rare earth modified carbon black. Then natural rubber latex （NRL） was added into the reactor. The system reacted at 85 ℃ with stirring for 1 h to prepare powdered HAF-Ln（OH）3/NR composites. The effects of the kind and content of Ln on the particle size distribution of P [ NR/HAF-Ln （OH）3 ] and mechanical properties of its vulcanizate were studied respectively. It is found that rare earth can help to get the powder of the composite, the product particle with a diameter less than 0.9mm will be get when the composites containing the compound of Ho, Er and Dy with dosage of 1.0, 1.0, O. 5 percent, respectively. The adding of Ln can improve the tensile strength and tear strength of the vulcanizate effectively, what＇s more, Er and Dy can decrease the permanent set of vulcanizate significantly. The SEM studies shows that P[ NR/HAF-Dy （OH）3 ] vulcanizate shows superior mechanical properties that depend primarily on the absence of free carbon black, the fine dispersion of carbon black in the rubber matrix and better polymer-filler interaction.     

桥梁热力管防冻融冰系统的数值模拟

热力管加热桥面融雪化冰对于保障交通安全具有重要意义。针对赤石大桥的地理环境和气象条件,建立了其热力融冰过程的数值模型,研究了热力管间距为100、150和200mm三种情况下融冰系统的热量传递过程和桥面温度变化规律。结果表明:在相同工况条件下,主桥向底面传递的热损失基本可以忽略,而引桥的热损失较大;在热力管层铺设2mm厚度的隔热材料,引桥向下传递的热量损失减少5%左右;从向桥面传递的热量来看,100mm间距融冰系统的融冰能力要远大于200mm间距融冰系统;在340.00 W/m2的融冰负荷情况下,当热力管外表面工作温度为25.00℃时,100mm间距敷设的热力管融冰系统,能使桥面平均温度在2.50℃以上,并且桥面温度场较为均匀,能有效融冰。     

规则六面体多重网格生成方法的研究

本文介绍了CFD前处理技术的重要性和网格自动生成技术的发展现状,根据多重网格法的基本思想和应用,开发了基于Windows平台的前处理软件,实现了规则六面体多重网格的自动生成。在进行网格划分时,该软件可以根据需要对边界进行疏密不同的局部单重网格划分,然后在单重网格基础上进行加密划分,最后建立粗细网格间的节点坐标映射,生成多重网格。采用此软件,对室内空气数值模拟中的典型几何模型进行了网格划分,生成了高质量的规则六面体网格,从而证明了该软件能有效且方便地应用于室内空气数值模拟中。     

V2F模型在室内空气流动数值模拟中与其他湍流模型的比较研究

介绍了V2F模型的表达式。对Annex20算例进行了模拟计算,将V2F模型、雷诺应力模型、标准K-ε模型、低雷诺数K-ε模型、RNGK-ε模型的模拟结果与其他研究者的实验结果进行了比较。结果表明,V2F模型在模拟室内空气流动中优于其他湍流模型。     

半封闭空间回转翻卸粉状物料扬尘机理研究

本文通过理论分析、现场实测和计算机模拟分析了半封闭空间回转翻卸物料时产生的气流及其分布,揭示了半封闭空间回转翻卸物料时扬尘的机理：物流的冲击会产生粉尘的飞溅,飞溅的粉尘数量主要与落差有关;气流是产生扬尘的主要原因。文中给出了气流的计算公式。为类似工程的通风除尘技术提供了理论依据。     

风系统中静压箱特性的研究及应用

分析研究静压箱的消声、阻力、均压等性能。实践证明，在风系统中，合理设计静压箱能提高风系统的综合性能。     

Non-stationary Buffeting Response Analysis of Long Span Suspension Bridge Under Strong Wind Loading

The non-stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non-stationary fluctuating winds with probabilistic model for non-stationary strong wind fields is first presented. Non-stationary wind forces induced by strong winds on bridge deck and tower are then given a brief introduction. Finally, Non-stationary buffeting response of Pulite Bridge in China, a long span suspension bridge, is computed by using ANSYS software under four working conditions with different combination of time-varying mean wind and time-varying variance. The case study further confirms that it is necessity of considering non-stationary buffeting response for long span suspension bridge under strong wind loading, rather than only stationary buffeting response.     

网格自动生成技术进展综论

网格自动生成技术是目前数值模拟中的关键技术之一。该文在分析大量的文献基础上,对网格自动生成方法进行了比较全面的总结,并指出它们各自的优缺点。同时指出了网格自动生成技术在计算流体力学(CFD)上的重要作用,分析了国内外在网格自动生成技术上的巨大差异,提出了国内开发CFD软件和进行网格自动生成技术研究的必要性。     

汽车空调车室内气流和温度场的数值模拟

运用稳态不可压缩雷诺平均N-S方程,k-ε湍流模型,采用有限容积和交错网格将计算区域进行离散,对汽车车厢内三维空气流场和温度场进行了数值计算,考虑了太阳辐射和人体散热对速度场和温度场的影响。结果表明人体散热对气流的流场和温度场有较大的影响,太阳辐射对流场影响较小,但对温度场有较大的影响。研究结果为客车内气流组织的优化设计和舒适性提供了数据支持。     

室内悬浮颗粒的数值模拟

应用多流体模型和小滑移模型模拟了一个1000级洁净厂房的流场、温度场和颗粒分布,并与实测数据进行了比较,认为在一定条件下多流体模型比小滑移模型更适合模拟洁净室中稀疏悬浮颗粒。