基于Fluent的超声波流量计水流特性研究

超声波流量测量技术是一种先进的流体流量测量方法.文中对超声波流量计测量原理进行了分析,并推导出流量计算公式;采用Fluent软件对水流特性进行了数值模拟,分析了管内流体的流场分布、压力分布规律.模拟结果显示超声波接收端与发射端液流存在漩涡,入口段中心线与水平管道中心线的夹角对测量精度影响显著.模拟结果与实际相符,对流量计结构的优化设计具有一定的借鉴意义.     

海上漂浮式输油管线内部流体流速引起管线变形的研究

通过对海上漂浮式输油管线进行受力分析,建立其内部流体流速变化对管线作用的数学模型.利用ADINA软件,采用流固耦合方法,对DN100野战输油管线进行了分析,研究了管线的变形情况,并将其与理论计算结果进行了比较,验证了该模型的可行性.     

平衡式波纹管补偿器

平衡工波纹管补偿器是利用流体力原理在一般波纹站偿器的基础上设计的一种新垢，国内外领域的管道偿器。从而使补偿器的应用进入了一个新的时期和高度。     

消浪平台工程建设对周边海洋环境的影响分析

文章通过建立海域水动力及泥沙输运研究模型,模拟了消浪平台工程建设对周边海洋环境的影响.研究发现:大潮时悬浮泥沙扩散速度较快且浓度下降迅速,对周围海洋环境的影响反而最小;小潮时潮流流速较小,工程悬浮泥沙以施工地为中心向四周扩散缓慢,形成浓度较高的包络面.因此,在大潮时进行施工较为适宜.     

测温元件保护套管对管道流体流态特征影响的模拟分析

文中对测温元件保护套管进行三维建模,采用Fluent软件对管道内流体进行模拟仿真和分析计算,并研究不同插入深度下管内流体的流态特征,为工程设计或安装施工提供参考。     

Fluent软件在膨胀节设计中的应用

针对Fluent软件流体计算能力应用于膨胀节设计中,介绍了在高温高流速介质下膨胀节温度场分布计算方法。膨胀节内流体介质为750℃的高温介质,且流速高达100 m/s。膨胀节采用双插式内衬结构,借助Fluent软件进行流热耦合计算,得出温度场分布情况。同时,基于Fluent软件对于通过波纹管流体的压降进行模拟,通过CFD-POST定义函数计算压降值。     

我国煤炭产消运空间格局分析

本文分析我国煤炭生产、消费、调运的空间分布及其演变,并综合考虑煤炭资源储量、生产、消费、调运等因素,对我国煤炭产、消、运区域类型进行划分。在此基础上,针对我国煤炭生产、消费、运输空间格局变化产生的新问题提出几点建议。     

内流式锥阀流场的数值模拟与结构优化

锥阀具有密封性能好、过流能力强、响应快、抗污染能力强等特点,在流体输送中得到了广泛的应用。应用PHOENICS流体计算软件及k-ε湍流计算模型,对内流式锥阀的内部流场进行了模拟仿真,研究了流量变化、开度变化对锥阀流场特性的影响。研究结果对分析锥阀的性能、进行流道的结构优化和实际工程应用都具有一定的指导作用。     

基于流体离散耦合的透水砖孔隙堵塞数值模拟研究

针对混凝土透水砖与复合砂基透水砖使用过程中内部堵塞路径无序化和不可视化而影响使用寿命的问题,文章运用流动动力学分析软件Fluent与流体颗粒分析软件EDEM,建立混凝土透水砖与双层砂基透水砖的流体离散耦合数值分析模型(FLU-EDEM),选用五种不同粒径实体堵塞物,模拟采用三种级配组成方式在水流携带入渗过程中在两种透水砖中的滞留轨迹及水流渗透通道,分析混凝土透水砖与双层砂基透水砖不同深度堵塞量和堵塞区域分布演变过程,总结得出典型堵塞现象,揭示透水性能衰减规律和机理。     

洪水冲击管道的模拟分析

根据计算流体力学的原理和方法，以流场数值模拟为基础，利用大型流体计算软件对洪水冲击管道流场进行了模拟分析，得到了流场分布、压力分布情况，计算出了不同裸露程度管道在不同流速洪水冲击下的受力数值，分析了管道裸露程度对管壁受力的影响。     

Energy savings in transport

A decade of increasing Federal attention to urban transportation needs has culminated in the 1970 Urban Mass Transportation Assistance Act. This Act is intended to provide 10 thousand million dollars over the next 12 years in Federal assistance money to urban public transportation systems. This paper examines the needs of selected U.S. cities as a basis for (1) understanding the vast, various and complex transportation needs of urban areas throughout the country, and (2) assessing the sufficiency of these funds. The sample cities have been placed into three broad categories based on the state of development of their transportation systems. In Category I cities, the essential need is to ensure the survival of bus systems for the use of non‐drivers, or to provide some other viable alternative to the automobile; in Category II cities, the primary needs are to relieve auto congestion and to improve public transportation components, while in Category III cities, the primary need is massive investment to improve and to extend public transportation facilities. It is concluded that the presently intended Federal funding level for transportation will not meet the financial requirements of the Category III cities.     

纯电动汽车制动能量回收及储能策略研究

为解决纯电动汽车存在的制动能量耗损及续航里程不足等问题,通过对行车能量流分析的基础上,提出一种制动能量回收及储能策略,并利用ADVISOR软件建立整车制动能量回收策略仿真模型。选取UDDS城市道路工况进行仿真,结果表明所建立的控制策略可以对制动能量进行回收和储存,对于提高纯电动汽车续航里程提供了理论基础。     

基于再生制动能量吸收的地铁列车 节能运行研究

节能减排、低碳发展是城市轨道交通系统发展的重点,而优化列车运行过程是城轨系统节能降耗的重要途径之一,列车节能优化主要涉及两个维度,一方面可以优化单列车在站间的运行牵引策略,另一方面可以优化多列车运行的协同策略。从上述维度出发,本文建立了单列车运行优化模型和基于再生制动能量吸收的多列车运行优化模型,提出了协同优化的方法,设计了相应的算法求解。根据亦庄线运营实际数据,开展案例分析验证模型及节能效果。     

港口清洁能源应用的节能减排效果分析

本文讨论了清洁能源在港口的应用。以宁波港股份有限公司北仑第二集装箱(以下称"北二集司")码头清洁能源应用为例,采用能源替代比较法和排放因子法相结合,分析了清洁能源替代柴油和岸电的节能与减排效果,得出了清洁能源在集装箱码头应用技术成熟、节能减排效果良好的结论,可以为清洁能源在港口的推广应用提供借鉴。同时,为了推广LNG和岸电的使用,建议不将其纳入港口能耗统计范围内。     

基于EXTJS的城市轨道交通能源管理系统

城市轨道交通能源管理系统通过分析城市轨道线路、车站耗能体系基础上,实现全线路完备的能耗和用电设备电能质量的监测、数据分析功能,对持续改善轨道车站能耗有着极为重要的意义.本文详细介绍了一种基于ExtJS的城市轨道交通能源管理系统的实现方式.首先介绍了系统开发过程中使用的开源前端技术ExtJS,然后罗列了能源管理系统所包含的功能,最后简单介绍了系统的应用.实验室运行测试结果表明,该系统具有良好的可操作性、易维护性和准确性.     

外国军队军事运输能源保障体系研究

本文从建立高度管理机构和军地能源联席机制,统筹制定军事运输能源发展战略和完善的法规制度,大力探索新型军事运输能源应用和多元化保障格局构建,持续加强军事运输能源研究,切实提高军事运输能源使用效益等方面介绍了外国军队军事运输能源保障的主要做法。     

Energy policies for passenger motor vehicles

This paper assesses the costs and effectiveness of several energy policies for light-duty motor vehicles in the United States, using a version of the National Energy Modeling System. The policies addressed are higher fuel taxes, tighter vehicle efficiency standards, and financial subsidies and penalties for the purchase of high- and low-efficiency vehicles (feebates). I find that tightening fuel-efficiency standards beyond those currently mandated through 2016, or imposing feebates designed to accomplish similar changes, can achieve by 2030 reductions in energy use by all light-duty passenger vehicles of 7.1–8.4%. A stronger feebate policy has somewhat greater effects, but at a significantly higher unit cost. High fuel taxes, on the order of $2.00 per gallon (2007$), have somewhat greater effects, arguably more favorable cost-effectiveness ratios, and produce their effects much more quickly because they affect the usage rate of both new and used vehicles. Policy costs vary greatly with assumptions about the reason for the apparent myopia commonly observed in consumer demand for fuel efficiency, and with the inclusion or exclusion of ancillary costs of congestion, local air pollution, and accidents.     

Energy conservation and intercity freight transport

In this paper, the characteristics of intercity freight modal operations are investigated to evaluate the potential for achieving energy savings. It is determined that the greatest opportunities for conserving energy appear to rest with achieving modal shifts and operational improvements in truck and rail transport. To test this hypothesis, intercity truck and rail freight operations are analyzed to determine the relationships between energy consumption and the delivery of transport service. The energy consumption impact of alternative conservation measures are calculated, and in turn, evaluated in light of a series of institutional constraints. As such, this study goes beyond the characteristic cataloging of alternative energy conservation measures by conducting a disaggregated assessment of the effectiveness and feasibility of implementing such measures. This paper concludes that the potential for achieving energy conservation in the movement of intercity freight in general, and by truck and rail systems in particular, is limited, as well as shrouded by the complexity of the nature of the commodity itself, the commodity flow characteristics, and the market and institutional structure.     

Energy conservation in urban public transport

Urban public transport energy use is determined largely by the weight of the vehicle, and frequency of intermediate stops, imposing repeated acceleration/steady running/braking cycles, in which much of the kinetic energy is dissipated. Energy consumed for the same capacity and vehicle performance may be reduced by coasting, cutting vehicle weight, and use of regenerative braking, on electrically‐powered systems, to convert the otherwise wasted braking energy into useful form. Particular attention is paid to the last‐named, identifying results of past experience and recent simulations. Practical constraints limiting the amount of energy actually recovered are discussed, including proportion of vehicle weight braked electrically, receptivity of the supply system, stop spacing and number of vehicles operated simultaneously. Reference is also made to battery vehicles and flywheel energy storage.

It is suggested that considerable scope exists in urban electric rail operation for reduced energy consumption, as existing fleets are replaced by lighter weight vehicles, fitted for regenerative braking. Further savings may come from use of inverter equipment. Rate of fleet renewal may be an important factor. Buses are already much more energy efficient, and dramatic gains are unlikely. However, there is some scope for use of flywheel energy storage, and regenerative braking on trolleybuses.