涉外项目离心式消防水泵的设计选用要点

与石油化工流程泵的选用不同,离心式消防水泵的选用自成体系,涉外项目消防水泵的选择通常要求遵守NFPA 20标准.简要介绍了消防水泵及其驱动机、控制系统的选型要求,介绍了相关消防产品的认证,以及工程设计中所遇到的相关问题.     

构建现代城市的多元化特色空间——湖北省京山县人民广场规划设计投标方案介绍

在详细分析京山县人民广场设计背景以及对现状用地和周边环境进行认真调查的基础上 ,介绍了该投标方案的设计内容 ,其中包括规划定位和设计目标、功能布局和空间设计、景观组织和交通组织、设计意境等 .本设计不追求气魄 ,旨在寻求功能的多元化和绿色的生态化     

分布器结构对气固鼓泡流化床内气相分布影响的数值模拟

根据双流体模型,利用计算流体力学软件Fluent 6.3,在布风板开孔率Φ=3.86%时,对6种布孔方式不同的流化床中气相的分布特性进行了数值模拟,得到了各布孔条件下气相分布规律。结果显示,均匀布孔流化床内产生大量的气泡,气泡分布不均且存在大片流化率很低的区域。在各不均匀布孔流化床中,大小孔间隔排布布风板流化床(E型布风板流化床)内产生的气泡相对较小且分散性较好,气相速度矢量分布较分散均一,流化效果最好。与均匀布孔流化床相比,E型布风板的流化床轴向气相压力脉动更小,径向等压线分布更平缓,表现出轴向和径向气相分布更均匀,对鼓泡流化床的优化设计最有参考价值。     

排列方式对Y形单元厚屏频率选择表面传输特性的影响

厚屏频率选择表面（TFSS）是在薄屏FSS基础上,通过增加金属屏厚度,构成一种波导单元传输模式的新型FSS,使其具有更好的中心频点稳定性和工作带宽特性。本文通过设计一种Y型单元的TFSS结构,并利用矩量法,研究了单元排列方式对其传输特性的影响。结果表明：TFSS的工作带宽较薄屏FSS的工作带宽大,且随着单元排布紧密程度上升;随着单元排布紧密程度上升,透过率和带宽都呈上升趋势;电磁波正入射较斜入射的工作带宽大,透过率随着单元排布紧密程度上升,而趋于稳定;随着金属屏厚度的增加,透过率和工作带宽都呈减小趋势。     

冷却孔复合角和排列方式综合作用对平板气膜冷却效果的影响

研究复合角和排列方式综合作用对平板气膜冷却效果的影响。采用数值模拟的方法,保持射流圆孔尺寸、间距及倾斜角不变,分别对四种孔阵的平板气膜冷却进行了流动和传热的分析。利用Realizable k-ε湍流模型,标准壁面函数边界处理和SIMPLE算法,分析速度、涡量、冷却效率,对比冷却孔复合角和排列方式综合作用对平板气膜冷却效果的影响。结果显示:复合角和叉排同时存在时可改善平板展向上的冷却效果,而在平板流向上对冷却效果的影响不明显。结合吹风比得出较优的孔排方式。     

Developing electrochemical measurements in order to assess anti-corrosive coatings more effectively

The aim of this project was to check reproducibility of results obtained using NOCS (no connection to the substrate) arrangement of the electrochemical noise method (ENM). NOCS involves taking measurements from three nominally identical areas on the coated surface. Thus, no electrical connection to substrate is required. In practice the areas are not identical and various arrangements for connection of the three cells were tried to see if the individual areas could be separated out and whether the individual resistances could be computed. Also different ways of calculating the R_n (noise resistance) and R_sn (spectral noise resistance) parameters were attempted to see which one gave the best comparison with the more standard EIS measurements. The maximum entropy method was recognized to be the most useful for comparison with EIS, as well as for graphic evaluation of results. Regarding distinguishing three areas using different connection arrangements, it was possible to identify the situation when one of the three values was different to the other two. However further experiments are needed before it will be possible to confidently assign an R_n value to each individual area.     

重钙装置改产磷铵后氨化造粒机内部构件的配置研究

重钙装置改产磷铵后,造粒机内的物料行为发生了变化,即“料浆涂布－水分蒸发－氨化反应”这一物理化学过程。喷氨孔与水平线的夹角是影响这一过程的重要因素,本文对夹角的确定进行了理论分析。在实验基础上,对造粒机预中和料浆喷头位置、氨分布管的长度和角度进行了重新配置。生产表明,重新配置的造粒机内部构件具有很好的造粒效果。     

盛水桶注射模气嘴抽芯结构分析

分析了洗衣机盛水桶模具常用气嘴抽芯结构的特点及在生产过程中存在的问题,设计出相对较好的结构,通过生产验证,该设计既解决了气嘴壁厚不均问题,又提高了气嘴抽芯机构的使用寿命。     

椭圆形换热管安放形式对换热效率的影响

对椭圆形换热管横置和竖置两种安放形式的换热器进行了数值模拟,分别研究了不同进口速度时,换热器壳程的出口压差、管壳程出口温度和壳程单位压降下的换热系数。对计算结果进行分析。结果表明:在该计算工况下,换热管竖置时其单位压降下的传热系数要高于换热管横置时单位压降下的传热系数。     

Laser-Based Measurement of Gas–Liquid Two-Phase Flows in Micro and Mini Channels using Multiple Photodiode Arrangement

Two-phase flow measurement is important in process and chemical industries. In the present work, a measurement technique for the characterization of two-phase flows using a laser and an arrangement of the photodiodes is proposed and tested. Two-phase flow experiments were carried out in 1.80, 3.14, and 4.68-mm-diameter glass tubes. A high-speed camera was used to analyze the various optical patterns formed by a stationary laser beam on a screen during bubbly, slug, and stratified flows, which have been discussed in detail in Navisa et al. (2015 Navisa, J., Balachandar, C., Arunkumar, S., and Venkatesan, M. (2015). Characterisation of gas-liquid two-phase flows using LASER patterns, Can. J. Chem. Eng., 93(9), 1678–1685.[Crossref], [Web of Science ®] , [Google Scholar]). Photodiodes are arranged on the screen based on high-speed camera recordings. A procedure is demonstrated to calculate the flow regime velocity and length based on the photodiode outputs. The designed nonintrusive instrumentation determines the two-phase flow parameters in real time for flow in optically transparent mini channels. The accuracy of the measurement technique and the limitations are also discussed.