涡街流量计测量系统不确定度的分析

通过分析涡街流量计在液体和气体流量测量应用中的工作原理,讨论了涡街流量计测量系统中仪器尺寸精度、斯特劳哈尔数、涡旋频率测量、温/压测量以及其它环节的系统不确定度分量和不确定度的合成。通过对测量系统不确定度的分析,提出了涡街流量计测量系统的改进方向以及涡街流量计的干标定问题,促进节能减排工作的进展。     

质量流量计在燃油管理工作中的应用

1质量流量计简介 质量流量计总称CORIMASS测量系统,型号为MFM1081K+F.该系统采用模块化设计,主要由转换器和传感器组成.其测量原理为科里奥利斯力(简称科氏力).即当一根管子绕着原点旋转时,让一个质点通过管子向外端流动,质量的线速度由零逐渐加大.也就是说质点被赋予能量,随之而产生的反作用力将使管子的旋转速度减缓,管子运动发生滞后.相反,让一个质点从外端通过管子向原点流动,质点的线速度由大逐渐减小趋向于零.也就是说质点的能量被释放出来,随之而产生的反作用力将使管子的旋转速度加快,管子运动发生超前.这种能使旋转着的管子运动速度发生超前或滞后的力就称为科氏力.质量流量计为"中德合资上海科龙光华仪器有限公司"生产的,其造价约为人民币6万元左右,厂家免费安装调试.     

一种大功率发动机油耗的测量装置

介绍了以科里奥利斯质量流量计为核心的大功率发动机油耗的测量装置,阐述了它的测量原理和测量结果.     

谈机车检修后的质量保养问题

论述了内燃机车检修后的质量保养的重要性,提出了解决机车质量保养方面存在的认识问题,走出机车质量保养的误区及机车检修后运用中保养的重点.     

内锥流量计与孔板流量计的压力损失及能耗研究

通过CFD流体软件对内锥流量计压力损失进行了数值模拟,实验介质为汽油与柴油的混合物。内锥流量计和孔板流量计经常使用于流体计量,在保证两种流量计流通面积相等的条件下,对它们的压力损失进行了比较。结果表明,内锥流量计的压力损失仅为孔板流量计压力损失的30%左右,将内锥流量计应用于流体计量,可以起到节能降耗的作用。     

LWQ型气体流量计

<正> 上海三林节能仪表厂(国营企业)目前生产的LWQ型气体流量计,它是一种国内唯一专业生产直接插入式涡轮气体流量计。该仪表解决了长期以来压缩空气流量计量困难较大的问题。经上海、北京、江苏等十几个省、市数百家企业应用后,反映良好,是各企业能源计量工作必备的精密仪表。     

加强蒸汽流量监测 提高蒸汽计量水平

企业的能源计量是能源审计、能源诊断、用能分析和节能管理的基础性工作,同时也为企业控制能源成本提供可靠依据。虹桥国际机场蒸汽流量计量系统经分析比较,选用了涡街流量计,并对流量计的安装点选择、使用与维护作了分析和经验介绍。     

发电厂供热系统管损分析及优化策略

通过对某电厂供热系统主要经济指标现状的分析以及供热流量计现场设备和系统状况的诊断,提出了造成供热管损较大的主要因素,进一步定量分析各种流量计特点对现有供热系统影响程度,得出了整个供热系统各工况下各关口流量计供热压力的损失量及主要原因,明确了供热系统节能降耗工作的方向和重点,通过针对性的供热系统性能策略优化及相应的改造措施,提出一种以测量精度高,压力损失小,宽量程比、方便定期校验的巴式流量计为主要计量装置的实时优化方案,达到电厂供热系统优化节能运行,进一步降低电厂供热能耗的目的。可为同类型燃煤供热机组节能降耗优化运行提供参考。     

提高DF7型机车柴油机基本转速的试验

1 问题的提出 DF_7型机车投入运用已有十几年,属于主型调车机车,对铁路运输生产做出了很大贡献,但在实际运用中也出现了一些质量问题,需要尽快解决。如因机车最低空转转速即基本转速偏低(400±10r/min)而引起的故障就有很多,表现之一为机车大     

GK1型机车无线遥控微机控制系统

为GK1型机车开发的无线遥控微机控制系统主要由无线遥控器、主控制器、燃油计量系统、面板显示器组成。软件采用模块化结构设计方法,实现了对机车运行特别是恒速运行的专家模糊控制。系统有自动运转、无级遥控、原有操作三种操作方式,增加了加速防空转、保压发车、故障诊断显示、数据记录等实用功能,并能准确进行燃油消耗的计量。系统装车运用后,效果良好。     

青藏铁路内燃机车选用油品的建议

通过对青藏铁路内燃机车的使用环境分析,提出了适用于内燃机车所使用燃油、机油的建议。     

基于价值损耗的燃料电池混合动力能量管理策略评价

为了评价燃料电池混合动力系统能量管理策略的经济性,对基于状态机和模糊逻辑2种能量管理策略的燃料电池混合动力叉车的价值损耗进行分析。首先,通过分析燃料电池和锂电池的工作特性,分别构建依赖实际工况的燃料电池单体电压衰减率模型和锂电池容量衰减率模型;同时定义计及燃料电池氢耗量的燃料电池混合动力系统的综合价值损耗指标。其次,通过测试叉车极限工况,计算燃料电池功率和锂电池容量,并根据母线电压确定锂电池SOC范围。最后,设计基于状态机和模糊逻辑的2种燃料电池混合动力叉车能量管理策略,并通过仿真分析在叉车一次循环工况下2种能量管理的价值损耗。研究结果表明:相较于模糊逻辑策略,采用状态机策略造成燃料电池寿命损耗提高7.81%,氢耗量提高1.89倍,锂电池寿命损耗减小21.33%。     

A direct methanol fuel cell system with passive fuel delivery based on liquid surface tension

The existing direct methanol fuel cell (DMFC) systems are fed with a fixed concentration of fuel, which are either a diluted methanol solution or an active fuel delivery driven by an attached active pump. Both approaches limit the power conversion density or degrade the overall efficiency of the DMFC system significantly. Such disadvantages become more severe in small-scale DMFCs, which require a high conversion efficiency and a small physical space suitable for portable electronics. In this paper, passive fuel delivery based on a surface tension driving mechanism was designed and integrated in a laboratory-made prototype to achieve consumption depending on fuel concentration and power-free fuel delivery. Unidirectional methanol-to-water smooth flow is achieved through the capillaries of a Teflon PTFE (polytetrafluoroethylene) membrane based on the difference in liquid surface tension. The prototype was demonstrated to exhibit a better polarization performance and to last for an extended operating time compared to conventional DMFCs. Its high efficiency and load regulation performance were also demonstrated in contrast to an active DMFC supplied with a constant concentration fuel. The fuel delivery driven by the liquid surface tension effect demonstrated here is believed to be more applicable for future small-scale DMFCs for portable electronics.     

基于Small RTOS51的油耗-转速测量系统的设计与实现

介绍一种智能型油耗-转速测量系统的设计与实现。基于P89V51RD2单片机和SmallRTOS51嵌入式实时操作系统,该系统实现了对内燃机油耗、转速的自动测量、记录等工作。油耗测量采用重量法,转速测量使用磁电式转速传感器进行测量;使用单片机进行控制,包括信号的采集、计算、保存、通讯等方面的工作。该系统具有体积小,重量轻,功能全的特点。     

Dynamic modeling and evaluation of solid oxide fuel cell - combined heat and power system operating strategies

Operating strategies of solid oxide fuel cell (SOFC) combined heat and power (CHP) systems are developed and evaluated from a utility, and end-user perspective using a fully integrated SOFC-CHP system dynamic model that resolves the physical states, thermal integration and overall efficiency of the system. The model can be modified for any SOFC-CHP system, but the present analysis is applied to a hotel in southern California based on measured electric and heating loads. Analysis indicates that combined heat and power systems can be operated to benefit both the end-users and the utility, providing more efficient electric generation as well as grid ancillary services, namely dispatchable urban power.Design and operating strategies considered in the paper include optimal sizing of the fuel cell, thermal energy storage to dispatch heat, and operating the fuel cell to provide flexible grid power. Analysis results indicate that with a 13.1% average increase in price-of-electricity (POE), the system can provide the grid with a 50% operating range of dispatchable urban power at an overall thermal efficiency of 80%. This grid-support operating mode increases the operational flexibility of the SOFC-CHP system, which may make the technology an important utility asset for accommodating the increased penetration of intermittent renewable power.     

Analysis of a solid oxide fuel cell and a molten carbonate fuel cell integrated system with different configurations

A solid oxide fuel cell with internal reforming operation is run at partial fuel utilization; thus, the remaining fuel can be further used for producing additional power. In addition, the exhaust gas of a solid oxide fuel cell still contains carbon dioxide, which is the primary greenhouse gas, and identifying a way to utilize this carbon dioxide is important. Integrating the solid oxide fuel cell with the molten carbonate fuel cell is a potential solution for carbon dioxide utilization. In this study, the performance of the integrated fuel cell system is analyzed. The solid oxide fuel cell is the main power generator, and the molten carbonate fuel cell is regarded as a carbon dioxide concentrator that produces electricity as a by-product. Modeling of the solid oxide fuel cell and the molten carbonate fuel cell is based on one-dimensional mass balance, considering all cell voltage losses. Primary operating conditions of the integrated fuel cell system that affect the system efficiencies in terms of power generation and carbon dioxide utilization are studied, and the optimal operating parameters are identified based on these criteria. Various configurations of the integrated fuel cell system are proposed and compared to determine the suitable design of the integrated fuel cell system.     

柴油机燃用乳化油并在进气道喷乙醇的节油研究

利用柴油机排气能量加热乙醇,将乙醇喷入柴油机进气道,并结合乳化油的燃烧技术,进行了柴油机台架实验,实现了柴油机运行中较大幅度的节油,最大节油率约为10％．单就柴油而言,其消耗可减少约16％．乙醇热解产生氢气和燃用乳化油这两种因素的共同作用是产生良好节油效果的原因．     

直喷式柴油机燃用F-T柴油时的性能与排放

煤通过Fischer-Tropsch（F-T）合成可以获得十六烷值高、硫和芳香烃含量极低的F-T柴油.在一台未作改动的单缸直喷式柴油机上对燃用F-T柴油时发动机的性能和排放进行了研究.结果表明,在相同工况下与燃用常规柴油相比,燃用F-T柴油时的滞燃期较短,预混燃烧放热峰值较低,扩散燃烧放热峰值较高,最高燃烧压力略低,最大压力升高率显著下降,燃油消耗率和热效率都得到了改善.燃用F-T柴油可同时降低CO、HC、NOx和碳烟排放,其中NOx和碳烟排放分别平均降低了16.7%和40.3%.研究表明F-T柴油是柴油机优秀的清洁代用燃料.     

A novel predictive power flow control strategy for hydrogen city rail train

Hydrogen-based vehicular traction has already reached a mature technological level and can replace the more polluting diesel engines. The adoption of this technology can also alleviate the carbon footprint issue of the rail trains running on non-electrified lines.This study presents a model and a numerical performance analysis of an electric hybrid train in an urban context. The train uses hydrogen as fuel and operates over non-electrified lines with zero local emission.The electric traction motors of the train are fed by a hybrid power unit consisting of several hydrogen fuel cell stacks operating independently in on/off mode and a set of flywheel energy storage devices.Each component of the power train is modeled separately and its operating limits are chosen on the base of technical literature.An innovative predictive logic to manage power flows is defined and proposed with the aim to minimize the fuel consumption. Furthermore, this approach uses a regenerative electrical braking and eliminates dissipative devices, like rheostats, which are commonly utilized onboard electric trains.This predictive approach is based on the optimal management of the power unit components according to the advanced knowledge of the data of the rail vehicle, the characteristics of path, drive cycle and payload for an established route.The fuel cell stacks operate accordingly to the average traction power requirement in each railway line section, whereas the flywheel energy storage system manages the dynamic power.A parametric model of the system and a respective software tool have been developed; this implementation, that incorporates many tunable parameters of the train and rail path, is able to simulate the rail train operating on a specific railway path by implementing the novel control strategy.An existing single track non-electrified line, designed again for urban service, has been selected as a case study to evaluate the performance of the proposed system.The specific fuel consumptions obtained with the novel control strategy and with a single fuel cell system operating at constant power are compared under the same operating conditions.The results highlight that significant fuel savings can be achieved.     

甲醇和甲醇重整气对直喷汽油机性能影响的对比研究

基于GT-Power并耦合层流火焰速度经验公式开展了甲醇和甲醇重整气对直喷汽油机性能影响的对比分析。首先分别基于双燃料层流火焰速度经验公式,求取了异辛烷-甲醇和汽油-甲醇重整气层流火焰速度,根据层流火焰速度计算出燃烧持续期,作为燃烧模型的输入变量,进而探讨了汽油掺混不同比例的甲醇及甲醇重整气对发动机性能的影响规律。研究结果表明:掺混甲醇重整气与直接掺混甲醇相比,发动机有效热效率和输出转矩明显增加,当量比油耗降低,CO排放水平相当,但NOx排放增加。尤其在稀燃条件下,掺混甲醇重整气使热效率增加明显,这说明燃料重整方式在提高直喷汽油机热效率方面更有应用潜力。