石南油田多相流管线工艺计算模型的选择

运用不同的模型对石南油田的一条多相流管线的压降进行了计算,与实测值相比,计算结果均不理想。因此针对该多相流管线提出了一种新的组合模型,经计算比较,该模型对石南多相流管线有足够的精度,能满足工程上的要求。     

多相流管线的内腐蚀直接评价方法

主要结合墨西哥的一条使用了该评价技术的多相流管线实例,介绍油、气、水混输的多相流管线内腐蚀直接评价（ICDA）技术,重点介绍了多相流管线ICDA的间接检测阶段。采用多相流瞬态模拟软件（0LGA）结合风险分析技术绘制出基于风险分析的内腐蚀敏感度剖面图,从而确定出管线最容易发生腐蚀的高风险临界位置。     

数字辐射流动可视化系统设计与实现

介绍了一种利用数字辐射成像技术来实现高压不透明输送管道中高固多相黏稠物料流动成像的^60Co数字辐射流动可视化系统。首先阐述了该数字辐射流动可视化系统的总体构成,包括系统的基本原理和研制概况,进而介绍了该可视化系统的性能指标以及功能特点。该^60Co数字辐射流动可视化系统以扫描方式工作,能直接获得数字图像,可用于高压不透明输送管道中密相固液多相流流动机理的研究,其应用对推动高固多相黏稠物料管道输送及处置技术的发展具有重要意义。     

广西某一级公路水泥混凝土路面抗滑耐久性衰减规律研究

为研究水泥混凝土路面抗滑耐久性衰减规律,文章以广西某一级公路芯样为研究对象,设计并开展循环磨损试验,对比总结磨损过程中路面表面的宏观形貌差异,及其磨损量、构造深度、摆值的变化特征。结果表明：混凝土表面磨损过程可分为净浆磨损、砂浆磨损及集料磨损磨光三个阶段;受混凝土表层与其内部强度差异影响,随磨损次数及磨损深度增加,磨损速率减小;混凝土表面磨损过程中摆值呈先降低后平稳的趋势,与其内部裸露的砂颗粒丰富了表面构造有关;与表面摆值相比,磨损作用对混凝土表面构造深度的影响更大。     

CFD数值模拟在分离海砂碎贝壳中的应用

将贝壳砂混合液通过结构设计,获得一定黏度值的强制旋涡非牛顿流场,利用砂与贝壳在流场中的流态差异,实现有效分离。通过CFD仿真计算调整多相流获得最佳的输入输出参数,制定出符合目标的多相流分离方案,并在流体仿真的基础上,加工一套与仿真模型基本一致的技术试验装置,以验证三相分离的效果。     

漏磁腐蚀检测器在输气管道中的运行速度分析

输气管道的漏磁腐蚀检测因为受到管线输气量大的限制 ,在检测过程中检测器的运行速度过快将直接影响着检测结果的准确性。推导了理论速度的计算公式 ,并就其与实际运行速度存在差异的原因从皮碗磨损和气体泄流 2个方面进行了详细分析。该分析对输气管道漏磁腐蚀检测器皮碗外径的设计、驱动皮碗个数、各皮碗应开的泄流孔大小及个数等有指导意义     

混输管路压降计算方法在工程上的应用

混输管路在油田的地面集输系统中应用日益广泛,而混输管路压降计算对于管路经济管径选取起决定作用.文中对气液两相混输管路压降计算简单总结,对均相流模型、分相流模型、流型模型的代表性计算方法进行了介绍,并通过具体工程实例对工程设计中常用的混输压降计算方法进行了对比.采用常用的多相流模拟软件进行校核,得出Beggs - Bri...     

燃油中催化剂颗粒对船舶柴油机的危害及对策

残留在燃油中的催化剂颗粒,在柴油机运行中会使喷油设备、活塞缸套、等运动部件磨损加剧,从而造成系统油大量流失,严重时引发扫气箱着火等危害,给柴油机管理带来麻烦。对于及早发现残留在燃油中的催化剂颗粒对柴油机的危害,本文提出了行之有效的、切实可行的对策。     

长输天然气管道内腐蚀直接评价应用研究

文中基于标准规定和研究成果，论证了气质工况参数、高后果区与风险评价结果等输入数据对长输天然气管道内腐蚀直接评价结果有重要影响；针对丘陵地区某天然气长输管道，用PipePhase软件进行多相流模拟计算开展间接评价预测，并对预测内腐蚀敏感管段进行了直接检测，验证了ICDA的有效性。应用实例分析表明，针对部分长输管道，仅依据临界倾角分析不能确定需直接检测的内腐蚀敏感度点，应进一步开展多相流动分析，为更高效地开展长输天然气管道内腐蚀直接评价提出了建议。     

FCC催化剂在垂直立管中的蠕动特性实验研究

在直径150 mm、高5000 mm竖直管的实验装置上,以FCC催化剂为固体颗粒物料,采用P V6型颗粒速度测量仪以及压力传感器测量不同颗粒质量流率下竖直管中的颗粒流动特性.实验结果表明:立管中颗粒流蠕动特性受颗粒质量流率的影响.对于实验用FCC平衡催化剂,在颗粒质量流率较小时,颗粒流动为密集流,颗粒流蠕动明显.随着颗...     

A causal encounter model of traffic collision avoidance system operations for safety assessment and advisory optimization in high-density airspace

The traffic collision avoidance system (TCAS) acts as a proverbially accepted last-resort means to resolve encounters effectively, while it also has been proven to potentially induce a collision in the hectic air traffic. Thus, new research considering the impact on safety is required to increase the airspace capacity based on a comprehensive analysis and accurate flight evaluation. In this paper, a causal encounter model is proposed to extend the TCAS logic considering the horizontal resolution manoeuvres, which could be used as the auxiliary supports when a potential collision is predicted in the vertical dimension. Based on the generated state space, the model developed in the graphical modelling and analysis software (GMAS), not only provides a better comprehension of the potential collision occurrences for risk assessment by representing the cause-effect relationship of each action, but also aids the pilots in the involved aircraft to make a cooperative and optimal option. Quantitative simulation results are conducted to validate the feasibility and effectiveness of the encounter model with horizontal resolution. The resulting collision scenarios are further investigated to illustrate that the risk rate of TCAS logic failures is expected to reduce by shortening the pilot's response delay, and the computational efficiency is competent in dealing with multi-threat scenarios.     

油气混输管道数据库管理平台开发

采用SQL Server 2005和Visual C#.NET软件建立了油气混输管道数据库,并开发了数据库管理平台,能够实现管道数据的录入、修改、删除、查询,温度、压力的计算和修正等功能。该数据库管理平台在工程实际管道和实验环道装置的数据基础上,对已有模型进行修正,使之适用于现场,并提出了查询插值的新方法,成为实现混输管道压降预测的有效途径。同时,该数据库可应用于工程设计建设及混输管道压降计算方法的研究。     

海底混输管道内部状态完整性分析

为保证某混输海管的安全运营,通过建立混输海管多相流动模型和腐蚀模型,分析海管典型运行工况参数与设计取值,得出管道多相流动参数分布规律、腐蚀速率主要影响因素和总腐蚀情况。结果表明：海管入口立管底部压力最高;管内沿线温度总体逐渐降低,具有轻微波动;平管上坡段和入口立管段持液率较高;液体流速对该管道腐蚀速率的影响最显著;入口立管段底部腐蚀速率最大,且均大于设计取值;腐蚀速率设计取值偏小。     

含水合物相变多相内流深水立管管内流动特征分析

在深海立管中,开采的天然气水合物受到环境因素和自身性质的影响,进行水合物的生成和分解等反应,使得管内流变成复杂的多相非平衡流,影响开采立管的安全性,容易引发安全事故.基于分子热力学,建立了天然气水合物在受温度压力变化影响下的生成分解相平衡模型,并在相平衡模型基础上考虑气液固三相的性质变化,得到由气液固各相连续方程、能量...     

Rail-road crossing impacts: an international synthesis

Rail-road crossings generate a range of transport, economic, social and environmental impacts. While much research has focused on selected impacts such as safety, little consideration has been given to wider impacts. The aim of this research was to therefore develop a holistic understanding of the impacts of rail-road crossings (both at-grade and grade-separated) and to identify key gaps in knowledge in this field. An international synthesis of rail-road crossing impacts was developed through a detailed literature review, which revealed a total of 18 different types of impacts associated with rail-road crossings. The review found that most research to date has focused on quantifying transport and economic impacts, particularly safety and road vehicle delay, with little consideration given to social and environmental impacts. A number of research gaps have been identified which provide a clear agenda for future research. These gaps include the use of empirical evidence to support impact assessments, and the need to better understand the impacts of grade-separating rail-road crossings in terms of safety, travel time variability, land use, traffic flow, rail vehicle delay, disability access, and crime.     

A method for relating type of crash to traffic flow characteristics on urban freeways

A method is developed to determine how crash characteristics are related to traffic flow conditions at the time of occurrence. Crashes are described in terms of the type and location of the collision, the number of vehicles involved, movements of these vehicles prior to collision, and severity. Traffic flow is characterized by central tendencies and variations of traffic flow and flow/occupancy for three different lanes at the time and place of the crash. The method involves nonlinear canonical correlation applied together with cluster analyses to identify traffic flow regimes with distinctly different crash taxonomies. A case study using data for more than 1000 crashes in Southern California identified twenty-one traffic flow regimes for three different ambient conditions: dry roads during daylight (eight regimes), dry roads at night (six regimes), and wet conditions (seven regimes). Each of these regimes has a unique profile in terms of the type of crashes that are most likely to occur, and a matching of traffic flow parameters and crash characteristics reveals ways in which congestion affects highway safety.     

Uni- and bi-directional pedestrian flow in the view-limited condition: Experiments and modeling

In this paper, the impact of vision on the uni- and bi-directional flow has been investigated via experiment and modeling. In the experiments, pedestrians are asked to walk clockwise/anti-clockwise in a ring-shaped corridor under view-limited condition and normal view condition. As expected, the flow rate under the view-limited condition decreases comparing with that under the normal view condition, no matter in uni- or bi-directional flow. In bidirectional flow, pedestrians segregate into two opposite moving streams very quickly under the normal view condition, and clockwise/anti-clockwise walking pedestrians are always in the inner/outer ring due to right-walking preference. In the first set of experiment, spontaneous lane formation has not occurred under the view-limited condition. Pedestrian flow does not evolve into stationary state. Local congestion occurs and dissipates from time to time. However, in the later sets of experiments, spontaneous lane formation has re-occurred. This is because participants learned from the experience and adapted right-walking preference to avoid collision. To model the flow dynamics, an improved force-based model has been proposed. The driving force has been modified. The right-walking preference has been taken into account. The fact that pedestrians cannot judge the moving direction accurately under limited-view condition has been considered. Simulation results are in good agreement with the experimental ones.