城镇燃气管道带压封堵局部应力分析

城镇燃气管道的安全运行是城镇居民安全用气的保障,针对城镇燃气管道泄漏带压封堵产生的局部应力问题,以补板修复方法为例,利用有限元分析软件ANSYS,分析内压、补板厚度和泄漏孔孔径等因素对孔结构受力的影响规律.结果表明:随着内压的增大,管道的边缘随之发生屈服,管道整体随内压呈正线性相关变化.当补口处的补板长度一定时,该位置...     

中压闭环气体流量标准装置压力控制系统

以中压闭环气体流量标准装置为研究对象,设计基于PLC的压力控制系统。给出控制系统的硬件结构和软件功能。运行测试结果表明:当流量点变化后,压力控制系统排气压力在小幅度下降后能够迅速稳定至设定值,且压力稳定性优于0.04%,能够满足闭环气体流量标准装置进行流量仪表检定的使用要求。     

高压天然气输送管道事故后果评估体系研究

分析了高压天然气输送管道事故特点,基于火灾模型、高压天然气有效释放速率模型及热强度阈值计算模型,确定了事故危险区域描述方法,同时在构建事故人员伤亡后果评分体系、事故直接经济损失后果评分体系及事故无形后果评分体系的基础上,建立了高压天然气输送管道事故后果评估体系,为长距离高压天然气输送管道的安全评价、风险管理奠定了坚实基础。     

复杂管系气柱固有频率的有限元法计算

采用有限元分析方法 ,对简单管道气柱的固有频率进行求解 ,其结果与用传递矩阵法求得的结果是一致的。对实验室复杂管系气柱的固有频率进行计算 ,分析了管道振动的主要原因     

天然气压力能回收利用研究进展及分析

随着我国长输管道(高压)的发展,管道内的高压天然气的压力能所具有的经济价值是不容忽视的,天然气压力能利用包括直接利用和间接利用,介绍了高压天然气(CNG)直接膨胀发电、天然气压力能用于制冷技术和一种改进的将天然气压力能用于冷热电三联供的方法与装置存在的问题及分析。     

压力管道的风险管理研究

系统地介绍了压力管道风险管理理论,分析了压力管道风险管理的必要性,并从压力管道风险识别、风险分析、风险估算、风险评价、风险决策和风险控制这几个方面阐述了几种压力管道风险管理的主要方法,并指提出了压力管道风险管理中应注意的问题。     

燃气管道泄漏模型的研究进展

泄漏速率是燃气管道扩散模拟和风险评价的重要因素,同时也是管道泄漏检测不可缺少的一环.通过对国内外泄漏速率计算模型的应用分析,探讨了燃气管线泄漏率计算的主要模型和分类方法,罗列了稳态模型下小孔模型、大孔模型和管道模型的计算式,并指出其适用范围.对于大孔模型,提出了高压和低压分开计算泄漏率的方式.对比一些非稳态泄漏模型指出...     

现有城市燃气管线接纳天然气能力的研究

通过试验研究,比较了厚白漆和聚四氟乙烯生料带这两种室内燃气管线螺纹接口密封材料对天然气的适应能力,同时对保持原状和经过干燥处理的埋地燃气管道橡胶密封圈进行了力学性能测试,考察了埋地管线橡胶密封圈经过多年煤气运行环境后力学性能的变化以及密封圈对天然气工作环境的适应能力,并对在役橡胶密封圈的剩余使用寿命进行了预测。     

天然气管线事故后果分析

天然气的主要成分是甲烷,爆炸极限低。文中就天然气管线火灾事故进行后果分析（包括个体风险和社会风险）,介绍了一种简便实用的事故概率计算方法,并用管线的死亡半径、死亡长度、致死率对事故造成的个体风险和社会风险进行定量风险分析。     

Effects of Turbulent Fluctuations on Nanoparticle Coagulation in Shear Flows

The effects of fluid turbulence on the coagulation of aerosols are studied quantitatively and qualitatively. Direct numerical simulation data is used to isolate the effect of the small or subgrid-scale (SGS) particle–particle interactions on nanoparticle coagulation in three-dimensional flows. The rate of particle growth is decomposed into the contribution of the large-scales and small-scales interactions. The contribution of the small-scale interactions is presented as a function of time, space, flow dynamics, and coagulation Damköhler number. Results show that small-scale interactions act to both increase and decrease particle growth. The probability density functions (PDFs) of the SGS growth rate exhibit a negative bias, which increases with time and coagulation Damköhler number. Additionally, PDFs conditioned on the Q-criterion suggest that the contribution of the small-scale interactions primarily act to reduce particle growth in regions characterized by fluid rotation.     

埋地管道施工的质量问题分析和处理

以140万d/a延迟焦化工程为例,文章分析了引起埋地管道施工质量问题的原因,提出地管质量缺陷存在于实体、行为、资料,集中于实体,影响实体的主要因素是人员和环境,特别是加强对人员施加影响效果史好,因此提倡"以人为本",建立和运行质量保证体系,是提高地管施工质量的关键.     

Pressure Fluctuations in Jet Spouted Beds

Jet spouted beds that consisted of a transparent Plexiglas cylindrical column of 1 m high and a conical base with cone angles of 30°, 36°, and 40° were used in this study. The particles used were spherical glass beads with an average diameter of 1.7, 2.1 and 3 mm, respectively, and particle size of 2.2 – 3.1 mm, non‐spherical rice particles. The effect of size and shape of particles, and static bed height on the minimum jet spouting velocity, and standard deviation of pressure fluctuations, was investigated. The results show that the minimum jet spouting velocity and pressure drop increased as the bed height and particle size increased. The minimum jet spouting velocity could be determined from the plot of standard deviation of pressure fluctuations vs. superficial gas velocity. The results obtained were in close agreement with the results of other methods in the literature.     

气体流量测量补偿算法在仪器仪表中的实现

介绍一种在 8位或 16位单片机上应用的理想气体流量测量的温度和压力补偿算法 ,本算法具有计算速度快、精度高、补偿实现方法简洁、性价比高等优点。     

Thermophoresis in Rarefied Gas Flows

Numerical calculations are presented for the thermophoretic force acting on a free-molecular, motionless, spherical particle suspended in a rarefied gas flow between parallel plates of unequal temperature. The rarefied gas flow is calculated with the direct simulation Monte Carlo (DSMC) method, which provides a time-averaged approximation to the local molecular velocity distribution at discrete locations between the plates. A force Green's function is used to calculate the thermophoretic force directly from the DSMC simulations for the molecular velocity distribution, with the under-lying assumption that the particle does not influence the molecular velocity distribution. Perfect accommodation of energy and momentum is assumed at all solid/gas boundaries. Earlier work for monatomic gases (helium and argon) is reviewed, and new calculations for a diatomic gas (nitrogen) are presented. Gas heat flux and particle thermophoretic forces for argon, helium, and nitrogen are given for a 0.01 m spacing between plates held at 263 and 283 K over a pressure range from 0.1 to 1000 mTorr (0.01333- 133.3 Pa). A simple, approximate expression is introduced that can be used to correlate the thermophoretic force calculations accurately over a wide range of pressures, corresponding to a wide range of Knudsen numbers (ratio of the gas mean free path to the interplate separation).     

Flow Regime Identification in a Slurry Bubble Column from Gas Holdup and Pressure Fluctuations Analysis

Analysis of gas holdups and pressure fluctuations are conducted in a slurry bubble column to study changes in flow regimes and comparisons are made with solid‐free bubble column. The pressure fluctuations are measured by fast response pressure transducers mounted on the column wall in the distributor and bulk regions. Air, tap water and 35 micron glass beads are used as the gas, liquid and solid phases respectively. Statistical analysis of pressure fluctuation data combined with gas holdup analysis provided information about flow regime transition and interesting insights into bubble size distributions and changes in flow structure.     

含缺陷压力管线概率失效准则的研究 I.压力管线重要度的模糊评价方法

指出压力管线重要度的评价是建立压力管线概率失效准则的基础。进而提出了一套石化、化工压力管线重要度的模糊评价方法 ,为含缺陷压力管线概率失效准则的研究奠定了基础     

制氢装置燃料用气流量/压力选择性-分程控制算法

燃料用气流量恒定是保证制氢转化炉燃烧控制稳定的重要条件。采取流量/压力选择性控制策略,在满足流量稳定的同时,又确保转化炉安全运行。为了避免生产负荷频繁升降可能带来的燃料用气流量的大幅波动,制氢装置采用CS3000系统实现滑动分程控制算法,达到了系统在不同生产负荷区域内能平稳运行的控制目标。     

气-固流化床压力波动功率谱指数衰减与阵发性混沌行为探讨

根据功率谱低频发散与阵发性混沌本质之间的联系，通过分析压力波动信号的功率谱指数衰减，并结合互信息函数分析，证实了流态化动力学所具有的阵发性混沌特性. 研究表明，随气速增加，压力波动层流区时间长度逐渐缩短，混沌越来越频繁地阵发，最终通向完全混沌状态. 此外，研究了层流区时间长度与雷诺数之间的关系，表明层流区时间长度随气速增加呈指数衰减，流态化动力学呈现出I型阵发机制.