Investigation of autoignition of propane and<Emphasis Type="Italic">n</Emphasis>-butane blends using a rapid compression machine

The effects of pressure and temperature on the autoignition of propane andn-butane blends were investigated using a rapid compression machine (RCM), which is widely used to examine the autoignition characteristics. The RCM was designed to be capable of varying the compression ratio between 5 and 20 and minimize the vortex formation on the cylinder wall using a wedge-shaped crevice. The initial temperature and pressure of the compressed gas were varied in range of 720-900 K and 1.6-1.8 MPa, respectively, by adjusting the ratio of the specific heat of the mixture by altering the ratio of the non-reactive components (N₂, Ar) under a constant effective equivalence ratio (ø_f=l.0). The gas temperature after the compression stroke could be obtained from the measured time-pressure record. The results showed a two-stage ignition delay and a Negative Temperature Coefficient (NTC) behavior which were the unique characteristic of the alkane series fuels. As the propane concentration in the blend were increased from 20% and 40% propane, the autoignition delay time increased by approximately 41% and 55% at 750 K. Numerical reduced kinetic modeling was performed using the Shell model, which introduced some important chemical ideas, represented by the generic species. Several rate coefficients were calibrated based on the experimental results to establish an autoignition model of the propane andn-butane blends. These coefficients can be used to predict the autoignition characteristics in LPG fueled SI engines.     

大亚湾核电站设备可靠性管理体系创新

大亚湾核电站自1994年商运以来取得了较好的业绩,在成功建立生产运行体系、设备维修体系及技术支持体系的基础上,通过不断引进、吸收和创新,现已基本建立一套有大亚湾特色的核电站设备可靠性管理体系,该体系的建立为大亚湾核电站长期安全稳定运行奠定了基础,本文重点介绍大亚湾核电站设备管理体系中的创新部分.     

RCM与风险分析技术的研究和应用

采用传统的以可靠性为中心的维修(RCM)与风险分析相结合的理论,对国内某炼油厂的常减压装置动设备进行了分析,提供了基于风险的RCM技术解决方案.论文中的分析方法既满足了对动设备开展可靠性分析的技术诉求,又继承了目前国内正在广泛开展的基于风险的管理(RBM)理念.     

AgNO_3显色法判断氯离子渗透深度的影响因素

采用不同配合比混凝土试样进行非稳态电迁移(RCM,rapid chloride migration)试验,研究AgNO3显色法对判断氯离子渗透深度的影响.结果表明:相比实际的氯离子渗透边界,采用AgNO3显色法测量的氯离子渗透深度值偏小,用RCM法计算的快速氯离子扩散系数较实际结果小;氯离子显色边界浓度对其扩散系数计算值的影响较大,试验中不同边界浓度对氯离子扩散系数的影响可达20%以上;水泥基材料物相中Ca(OH)2的含量对氯离子边界浓度有较大影响,存在一定的函数关系,Ca(OH)2的含量越高,氯离子边界浓度越大;掺入粉煤灰后,氯离子显色的边界浓度减小,用AgNO3显色法测得的渗透深度相应增大,采用RCM测得的氯离子快速扩散系数偏大.     

RCM在矿井提升机维修管理中的应用

预防维修,事后维修,RCM(以可靠性为中心的维修),各有长短,都有一定的适用范围。机械地规定某种型号的矿井提升机只采用某一种维修方式,不但不符合实际,而且又难以奏效。探讨一种更加符合现代管理实际与现实要求的矿井提升机维修模式,通过将状态监测与故障诊断、RCM相结合的方式,从而为矿井提升机的本质安全制定更为有效的维修策略。     

基于状态监测和故障诊断的RCM技术

针对传统的RCM技术存在非实时性和静态性等缺点,提出了一种基于状态监测和故障诊断的RCM技术。该技术将状态监测和故障诊断技术与传统的RCM技术相融合,克服了传统RCM技术的缺点,具有实时性和动态性。以某石化厂往复式压缩机为例,应用基于状态监测和故障诊断的RCM技术为该厂压缩机提供了维修策略,充分体现了该技术的实时性和动态性;基于状态监测和故障诊断的RCM技术对于提高设备故障检修效率、优化配置企业维修资源、提高企业经济效益等具有重大的工程实际意义。     

基于RCM需求的CMMS系统设计

根据以可靠性为中心的维修(RCM)的信息需求,计算机维修管理系统(CMMS)由设备的原始/运行/维修信息管理、财务信息管理、报表和数据输出与显示等子系统组成.各子系统管理的数据通过数据库进行存储,并按设备ID号索引.系统采用B/S模式,其构成含本地和远程数据采集、网络连接与服务器、及Web浏览器管理终端等.     

关于我国发电设备状态检修实施模式的探讨

状态检修实施中具体采用何种模式关系到实施效果和这项技术在我国推广的整体性的成败。根据对国内电力企业的特点和各种已有模式的分析，提出建议采用以cbm和RCM为主的模式，同时对相关问题进行了讨论，这些可为电厂进行状态检修规划时参考。     

基于GO法和RCM的惯性导航系统预测维修平台设计

针对惯性导航系统（INS）结构复杂、难以进行精确的系统可靠性分析和维修优化等问题,提出了一种基于GO法和以可靠性为中心的维修（RCM）的INS预测维修平台设计方法。利用GO法建立INS的可靠性分析模型—GO图,依据部件的寿命分布函数及时间应力采样更新部件的可靠度,实现部件残余寿命及系统可靠度的动态预测和评估。对不满足系统可靠性指标的INS,利用综合评价法权衡部件的贡献度、失效频度、检测度等影响因素,计算出各部件的维修优先度。最后按INS部件失效率恒定、失效率可变及故障部件隔离等不同情况分别进行仿真验证,结果证明所设计的INS预测维修平台是可行的、有效的,评价结果可为维修计划的制定提供参考依据。针对惯性导航系统（INS）结构复杂、难以进行精确的系统可靠性分析和维修优化等问题,提出了一种基于GO法和以可靠性为中心的维修（RCM）的INS预测维修平台设计方法。利用GO法建立INS的可靠性分析模型—GO图,依据部件的寿命分布函数及时间应力采样更新部件的可靠度,实现部件残余寿命及系统可靠度的动态预测和评估。对不满足系统可靠性指标的INS,利用综合评价法权衡部件的贡献度、失效频度、检测度等影响因素,计算出各部件的维修优先度。最后按INS部件失效率恒定、失效率可变及故障部件隔离等不同情况分别进行仿真验证,结果证明所设计的INS预测维修平台是可行的、有效的,评价结果可为维修计划的制定提供参考依据。     

Modelling the effects of climate change on the energy system—A case study of Norway

The overall objective of this work is to identify the effects of climate change on the Norwegian energy system towards 2050. Changes in the future wind- and hydro-power resource potential, and changes in the heating and cooling demand are analysed to map the effects of climate change. The impact of climate change is evaluated with an energy system model, the MARKAL Norway model, to analyse the future cost optimal energy system. Ten climate experiments, based on five different global models and six emission scenarios, are used to cover the range of possible future climate scenarios and of these three experiments are used for detailed analyses. This study indicate that in Norway, climate change will reduce the heating demand, increase the cooling demand, have a limited impact on the wind power potential, and increase the hydro-power potential. The reduction of heating demand will be significantly higher than the increase of cooling demand, and thus the possible total direct consequence of climate change will be reduced energy system costs and lower electricity production costs. The investments in offshore wind and tidal power will be reduced and electric based vehicles will be profitable earlier.