基于X列表的云应急管理体系构建

针对非常规突发事件的链式演化特征,为实现云应急环境下云应急管理体系内资源的智能化配置和敏捷高效的按需服务,对接入云端的应急资源、服务进行面向应急管理应用的分类,构建以"感知-决策-处置"为主线的云应急体系的按需服务机制;运用X列表(Bill of X,BOX)模型,分析云应急体系结构,提出面向云应急的X列表体系结构模型,建立列表要素间的语义描述框架和关联关系模型;设计了云应急模式下基于X列表的云应急平台的架构,以期为应急管理活动提供参考和依据。     

秦皇岛地区干旱趋势分析及人工增雨条件

通过分析秦皇岛地区水资源及人均占有率、气候干旱化之现状及秦皇岛地区降水的特点,发现秦皇岛降水有明显日变化特征（凌晨1～2时和傍晚17～18时降水量较大）。从化学制剂的选择、碘化银成核环境确定、积云增雨的高度判断三个方面提出了人工增雨作业条件,在作业实践中取得了良好效果。     

Reaction zone structures and propagation mechanisms of flames in stearic acid particle clouds

Reaction zone structures and propagation mechanisms of two representative flames established in stearic acid (CH₃(CH₂)₁₆CO₂H) particle clouds have been investigated. The reacting zone structure was examined by using a micro-electrostatic probe and a high-speed schlieren system. A distinct difference was observed in the ion current fluctuations recorded across the two representative flames propagating through the clouds of the same total mass density of particles and different mass densities of the particles smaller than 60 μm in diameter. When the mass density of smaller particles was high, a single peak was recorded in the ion current fluctuation. On the other hand, when the mass density of smaller particles was low, multi-peaks of various heights and widths were recorded. In the former case, the single peak was considered to be attributable to a unitary and a relatively thin flame started burning in vapor generated by the evaporation of smaller particles in the preheat zone. The flame propagation mechanism in this case was inferred to be similar to that of a usual hydrocarbon–air premixed flame, although the reaction zone thickness is much larger than that of the premixed flame. In the latter case, the multi peaks of various shapes were considered to be attributable to strong combustion at blue spots far behind the schlieren front. The flame propagation in this case was inferred to be supported by the heat release due to combustion at the blue spots.     

A method for simulation of vapour cloud explosions based on computational fluid dynamics (CFD)

The effectiveness of the application of CFD to vapour cloud explosion (VCE) modelling depends on the accuracy with which geometrical details of the obstacles likely to be encountered by the vapour cloud are represented and the correctness with which turbulence is predicted. This is because the severity of a VCE strongly depends on the types of obstacles encountered by the cloud undergoing combustion; the turbulence generated by the obstacles influences flame speed and feeds the process of explosion through enhanced mixing of fuel and oxidant. In this paper a CFD-based method is proposed on the basis of the author’s finding that among the various models available for assessing turbulence, the realizable k-? model yields results closer to experimental findings than the other, more frequently used, turbulence models if used in conjunction with the eddy-dissipation model. The applicability of the method has been demonstrated in simulating the dispersion and ignition of a typical vapour cloud formed as a result of a spill from a liquid petroleum gas (LPG) tank situated in a refinery. The simulation made it possible to assess the overpressures resulting from the combustion of the flammable vapour cloud. The phenomenon of flame acceleration, which is a characteristic of combustion enhanced in the presence of obstacles, was clearly observed. Comparison of the results with an oft-used commercial software reveals that the present CFD-based method achieves a more realistic simulation of the VCE phenomena.     

Modeling the two-phase cloud evolution from instantaneous flashing release using CFD

Computational Fluid Dynamics (CFD) approach has been successfully applied to simulate the small-scale instantaneous flashing release experiment by Pettitt. A model for dispersion of the release event is provided based on relevant theories and existing experimental data. An application of the CFD method to the dispersion simulation is illustrated. Furthermore, a new methodology based on discrete phase model for setting computational initial conditions is provided. An initial expansion and subsequent turbulence dispersion can be characteristically identified from both volume and temperature variation of the cloud obtained by the simulation. The possible mechanism for these phenomena has also been discussed and analyzed. The study deepens the understanding of the physical process of this event and provides one more reliable tool for relevant safety systems.     

液化石油气站储罐区火灾爆炸危险性分析与安全措施

选择具体的液化石油气储配站,分析了该站的危险特性、危险产生的途径及可能造成的后果。在没有任何防护措施的情况下,采用蒸气云爆炸和沸腾液体扩展蒸气云爆炸模型,对该站一个50m3储罐发生泄漏造成的火灾爆炸事故后果进行预测,得出火灾爆炸后的安全距离为大于211．0m。在储配站不能满足此安全距离的基础之上,从防止产生爆炸性气体环境、消除点火源和抑制事故扩大三方面来提出有效的安全措施,降低事故发生的概率及事故造成的损失。其中,站址选在全年最小频率风向的上风侧且周围空旷的地区,罐上设置液位计、压力表、温度计及可燃气体报警器可防止产生爆炸性气体环境;罐及管道设静电接地,法兰用铜线跨接,站内设警示标志可消除点火源;生产区与辅助区间设置隔离墙,罐区周围设置砖混围堤,罐上设安全阀可抑制火灾爆炸事故扩大。     

2000年来中国生态状况时空变化格局

21世纪以来,我国在经济快速发展的同时高度重视生态环境保护,一系列生态修复工程和空间管控措施使生态状况发生了巨大变化;然而目前对于全国生态状况宏观格局的认识仍十分有限。借助 Google Earth Engine（GEE）遥感云计算平台,采用主成分分析方法和MODIS数据构建的绿度NDVI、热度LST、湿度WET和干度NDSI四个指标,生成长时间序列的遥感生态指数RSEI数据集,完整刻画了中国2000年来生态状况的时空连续变化格局。研究发现:在空间格局上,东南沿海地区生态状况优于西北地区;变化趋势上,全国生态状况除上海、西藏和澳门之外均显著改善,RSEI增长最多的三个省份为山西、陕西和河北。进一步采用遥感云计算定量评价了2000年来生态状况变化的宏观格局,以期为国土空间管控和生态保护提供科学支持。     

Effect of inert species on the laminar burning velocity of hydrogen and ethylene

The maximum laminar burning velocity (LBV) of a fuel-air mixture is an important input parameter to vapor cloud explosion (VCE) blast load prediction methods. In particular, the LBV value has a significant impact on the predicted blast loads for high reactivity fuels with the propensity to undergo a deflagration-to-detonation transition (DDT). Published data are available for the maximum LBV of many pure fuel-air mixtures. However, little test data are available for mixtures of fuels, particularly for mixtures of fuels and inert species. Such mixtures are common in the petroleum refining and chemical processing industries. It is therefore of interest to be able to calculate the maximum LBV of a fuel/inert mixture based on the mixture composition and maximum LBV of each component.This paper presents measured test data for the maximum LBV of H₂/inert and C₂H₄/inert mixtures, with both nitrogen and carbon dioxide as the inert species. The LBV values were determined using a constant-volume vessel and the pressure rise method. This paper also provides a comparison of the measured LBV values with simplified LBV prediction methods.     

Effect of ignition delay on explosion parameters of corn dust/air in confined chamber

This paper presents the explosion parameters of corn dust/air mixtures in confined chamber. The measurements were conducted in a setup which comprises a 5 L explosion chamber, a dust dispersion sub-system, and a transient pressure measurement sub-system. The influences of the ignition delay on the pressure and the rate of pressure rise for the dust/air explosion have been discussed based on the experimental data. It is found that at the lower concentrations, the explosion pressure and the rate of pressure rise of corn dust/air mixtures decrease as the ignition delay increases from 60 ms; But at the higher concentrations, the explosion pressure and the rate of pressure rise increase slightly as the ignition delay increases from 60 ms to 80 ms, and decrease beyond 80 ms. The maximum explosion pressure of corn dust/air mixtures reaches its highest value equal to 0.79 MPa at the concentration of 1000 gm⁻³.     

干旱区云凝结核分布及其影响因子的观测研究

利用DMT CCN仪对宁夏盐池、银川地区地面及高空的云凝结核(CCN)进行实时连续观测.大量资料分析结果表明, CCN日变化明显,受人为因素影响,清晨和傍晚出现高值.夜晚温度与CCN浓度呈正相关,白天相反;强降水对CCN具有一定冲刷作用;沙尘气溶胶没有有效增加盐池地区的CCN浓度.与华北地区比较,银川、盐池地区CCN浓度偏低.此外,研究表明,过饱和度越高,活化CCN浓度越大.根据N=CSK拟合活化谱,银川属于典型大陆性核谱.由于云内清除作用,高空CCN浓度下降明显,但逆温层的存在使得该区CCN浓度累积增加.