Numerical investigation of light gas release,stratification and dissolution in TH22 test facility using 3-D CFD code GASFLOW-MPI

An accurate prediction of the hydrogen behaviors in the accident and management process is a crucial topic for both the hydrogen safety assessment and safety analysis in the confined enclosure like the containment of the nuclear power plant (NPP). Hence, the hydrogen behaviors including the transient light gas release, stratification and dissolution in the TH22 test facility for the NPP containment are analyzed and compared using the 3-D CFD code GASFLOW-MPI in this study. In this paper, the light gas helium is adopted as a substitute for the hydrogen in the calculations in accordance with the experiment. Firstly, the detached eddy simulation (DES) turbulence model, 3-D numerical model and experiment setup are introduced. Then, the hydrogen behaviors with the GASFLOW-MPI including the light gas release, stratification and dissolution are analyzed and validated with the experiment data. In addition, the velocity profiles, light gas concentrations, dimensionless numbers and temperature distributions are evaluated for the characteristics of the hydrogen behaviors. The results indicate that the calculation results agree well with the experiment data. Foremostly, the relative errors between the calculation results and experiment data during the phase of the dissolution of the light gas cloud are within 11.9%. Meanwhile, the relative errors of the time for the complete dissolution during the phase of the dissolution of the light gas cloud are within 5.0%. For the light gas release and stratification phase, the jet flow dominates as the Froude (Fr) number exceeds 10 during the time t = 600 s–800 s. Additionally, the time averaged centerline velocity and light gas concentration after the potential core region decay with a slop of 1/z which coincide with the theoretical jet limit. Lastly, the light gas concentrations and temperature distributions in all three phases are captured clearly with the GAFLOW-MPI. It demonstrates that the GASFLOW-MPI can accurately described the details of the related hydrogen behaviors in the accident and management process in the confined enclosure like the NPP. This paper can provide guidance for the numerical computation of the hydrogen safety issues in the confined space.     

基于最小方差的声线跟踪自适应分层算法

针对高精度水声定位系统中定位精度与计算量相互矛盾的问题,提出了基于最小方差的声线跟踪自适应分层算法。该算法根据声速在有限范围内规律变化的特点,对声速剖面全局搜索,通过各段声速散点到其拟合直线的总方差表示拟切分段与原始声速剖面的差别,利用最大差别找出最佳切分点,保留原始声速剖面特征,实现对声速剖面的简化。实验结果表明,该算法在保证定位精度的同时能够提高计算效率,具有良好的工程应用价值。     

Experimental study on the effect of lateral concentrated smoke extraction on smoke stratification in the longitudinal ventilated tunnel

Smoke is the main cause of death in tunnel fires. It is one of the important measures to maintain smoke stratification in the early stage of tunnel fire. This article focused on experimentally studying the combined effect of lateral concentrated smoke extraction and longitudinal ventilation on the smoke stratification, which never be revealed before. The velocity of the smoke layer and air layer, vertical temperature distribution, and the flow patterns of the smoke were measured. It was found that the longitudinal ventilation and lateral concentrated smoke extraction would affect the flow of the smoke and change the shear velocity between the smoke layer and air layer, then, the patterns of the smoke layer will be affected. And the flow patterns with Froude (Fr) number can be classified into three categories: (a)Fr < 0.6 , with stable smoke stratification; (b) 0.6 < Fr < 0.85 , with a stable smoke stratification but the blurring interface; and (c) Fr > 0.85 , the smoke layer is completely unstable. The result can provide a reference for ventilation design of immersed tube tunnels.     

车间内钢筋砼基础控制爆破拆除

介绍了用分层装药法拆除车间内钢筋混凝土基础的设计、施工，此工程的设计参数和施工方法对类似工程有一定的参考价值。     

底板突水的专家评分层次分析预测与评价

借助于防治水领域知名专家的实践经验和防治水知识 ,运用层次分析法 ,考虑影响底板突水的多方面因素 ,建立底板突水专家评分 层次分析预测系统 ,既总结和运用了现场实践经验 ,又能提高预测预报的成功率与准确性 ,为煤矿安全生产提供保证     

液化石油气储罐的热分层及安全设计对策

研究了液化石油气储罐在火灾作用下的热分层现象和规律，并分析了热分层对储罐响应的影响，提出了储罐安全设计的原则和建议。     

祈东矿新生界松散层的工程性质研究

在安徽省宿州市的祁东矿区,取五个钻孔中新生界松散层不同深度的土样,进行物理性质指标和部分力学指标的测定,初步明确了这个地区的土的物理力学性质。     

国外城市贫困问题研究

当前我国的城市贫困问题日益突出，但城市地理学者对这一社会问题的研究很少，且研究深度不够。旨在从城市贫困的含义和界定、城市贫困的特征、城市贫困产生的背景、产生原因及其应对措施等方面，对国城市贫困问题的研究做系统综述，较全面的介绍国外城市贫困问题的研究概况，以引起我国城市地理学者对这一问题的关注。     

基于层次分析法的可拓学理论在地下洞室岩体质量评价中的应用

基于可拓工程方法,在物元模型理论的基础上建立了洞室岩体质量评价的物元模型,提出采用层次分析法计算物元模型中各评价指标的权系数的方法。通过实际洞室岩体质量等级的关联度计算,对水布垭水电站地下厂房的围岩岩体质量进行了评价,得出与现场实际相符合的结论。研究结果表明:层次分析法用于确定洞室岩体质量评价指标的权系数是可行的,并且洞室岩体质量的可拓学评价能够较好地反映洞室岩体的质量等级,具有较好的适用性。