计算机在冷库设计制冷计算中的应用

本文阐明了以BASIC语言编写的冷库设计制冷负荷计算程序的结构和使用。利用该程序可以运算并输出各冷间的冷却设备负荷及不同蒸发温度系统的机械负荷的计算结果,以便在制冷工艺设计中为选配冷却设备和制冷压缩机等制冷设备提供经济可靠的基础数据。该程序中的计算公式有关参数的选取一律按照中华人民共和国国家标准《冷库设计规范》GBJ72—84的规定。该程序具有相当的通用性,对于不同类别和规模的冷库(不包括制冰)均可使用。本程序可供从事制冷工艺设计的工程技术人员在冷库设计过程中采用。可使设计者从繁琐的重复计算中解放出来,提高冷库的设计效率。     

LNG冷能用于冷库的分析

本文通过对LNG冷能用于冷库的两种制冷系统进行分析,对比各自的优缺点。通过分析,LNG冷能应用于冷库的直接蒸发制冷系统发展空间较大,换热效率及安全性比乙二醇溶液蓄冷系统高。比较了利用LNG冷能的直接蒸发制冷系统与常规机械制冷系统的差异和投资及运营成本。结果表明,利用LNG冷能的直接蒸发制冷系统的耗电量远远低于常规机械制冷系统,LNG冷能利用于冷库制冷系统有很大的发展空间。但从制冷系统的安全性、可靠性、冷源供应等方面综合考虑,常规机械制冷系统更加成熟稳定。     

冷库制冷冷媒选择与节能方法探讨

目前冷库制冷冷媒主要有：氨（R717）,氟利昂（大部分采用氟利昂R22）。这两种工质各有优缺点,选用不同的工质作为制冷系统的制冷剂,冷库的制冷设备、制冷系统配置均有很大不同,对冷库初投资、运行费用及其日常维护管理有很大影响。所以,在设计冷库制冷方案的初期应该针对所设计冷库的实际情况,     

船舶伙食冷库的设计分析

船舶伙食冷库是船舶上重要的生活设施之一，起着保障船员在航程中营养的均衡和食品质量安全作用。文章根据笔者多年的设计经验，在伙食冷库制冷系统的设计、制冷压缩机和设备阀件的选配、冷库隔热结构、自动调节方面，进行了分析，提出了一些建设性的意见。     

大型冷库计算机网络自动控制系统

根据冷库制冷工艺的要求,提出-种基于现场总线技术的冷库计算机网络自动控制系统,并详细介绍了自动控制系统的组成、系统功能和关键技术.解决了传统DCS控制系统中存在的问题,减少了系统布线,提高了冷库运行的可靠性和自动化水平,降低了能耗.     

我国氨系统冷库安全现状及发展建议

基于我国氨系统冷库的安全现状和发展趋势,从冷库设备陈旧、搬迁困难等方面分析了冷库现存的安全隐患。针对我国的冷库行业特点,提出了冷库设计应标准化和冷库系统应高度自动化;针对安全管理,建议优化监测点和监测预警技术;针对泄漏处置,建议物理和化学方法相结合的无害处理方式。为我国氨系统冷库的改造和新建提供有效的技术方案。     

冷库温度等级标准的制定

我国的冷库经过三十余年的建设,各种类型和规模的冷库遍及全国已初步形成一个冷藏网,这对促进食品的生产、调运、销售、繁荣市场起了很大的作用。在冷库建设中,从设计到施工、从科研到生产、管理都已积累了一定的经验,冷库设计规范和各系统的冷库管理办法也已各自形成。但是目前对冷库的温度标准,还只是按产品的分类定一个设计温度,如冻鱼冷藏间,不论大小冷库均采用-18℃,尚无温度的等级标准,因此在设计、使用中存在不少问题。所谓冷库温度等级标准,就是按温度标准把冷库分成若干等级。在这每一个温度等级中贮藏什么样的食品,将在保证质量的前提下,由货主根据实际情况自行选择,这将使冷库的建设和技术经济管理工作更趋于合理。     

对某冷库工程实例的分析

介绍开封空分集团制冷设备工程公司承建的一座冷库的库体结构、制冷系统、水冷系统,并分析其设计思路。     

冷库安装中常见问题与应对措施

文章分析了冷库安装中经常出现的标高、设备基础、设备就位、给排水、通风、库板切割等方面存在的问题、原因、影响及预防措施,可供冷库设计施工人员参考。     

超大型物流冷库的特点及自动控制节能措施

综合超大型物流冷库的特点,从节能的角度分析能够产生节能效果的各种构成;采取的解决方法是通过对冷库的设计、设备选型、操作规程等方面进行优化,并且通过自动控制系统实现工艺控制流程以及自控的节能方法与途径。     

Operational failure experience of fault-tolerant digital control systems

Fault-tolerant digital control systems (F-T DCSs) can theoretically achieve extremely high reliability, i.e. high mean time between failures (MTBFs). However, in actual applications theoretical MTBFs are idealized goals, and even the more modest goals can only be achieved with great effort at the design stage (particularly software design) and with excellence in operation/maintenance throughout the life of the system. This paper discusses the reliability performance of F-T DCSs, including a presentation of actual failure experience from 20 different computer system installations. Particular emphasis is given to identifying major contributors to system unreliability and comparing different types of F-T DCS architectures.     

Reliability improvement via taguchi's robust design

Taguchi's robust design strategy, whose aim is to make processes and products insensitive to factors which are hard or impossible to control (termed noise factors), is an important paradigm for improving products and processes. We present an overview of the strategy and tactics for robust design and demonstrate its usefulness for reliability improvement. Two important components of robust design are a criterion for assessing the effect of the noise factors and experimentation according to specialized experimental plans. Recent criticism of Taguchi's criterion and his analysis of its estimates has led to an alternative approach of modelling the response directly. We give additional reasons for using this response-model approach in the context of reliability improvement. Using the model for the response, appropriate criteria for assessing the effect of the noise factors can then be evaluated. We consider an actual experiment and reanalyse its data to illustrate these ideas and method.     

An analytical approach to quantitative effect estimation of operation advisory system based on human cognitive process using the Bayesian belief network

The design of instrumentation and control (I&C) systems for nuclear power plants (NPPs) is rapidly moving towards fully digital I&C systems and is trending towards the introduction of modern computer techniques into the design of advanced main control rooms (MCRs) of NPPs. In the design of advanced MCRs, human–machine interfaces have improved and various types of decision support systems have been developed. It is important to design highly reliable decision support systems in order to adapt them in actual NPPs. In addition, to evaluate decision support systems in order to validate their efficiency is as important as to design highly reliable decision support systems. In this paper, an operation advisory system based on the human cognitive process is evaluated in order to estimate its effect. The Bayesian belief network model is used in the evaluation of the target system, and a model is constructed based on human reliability analysis event trees. In the evaluation results, a target system based on the operator's cognitive process showed better performance compared to independent decision support systems.     

Ice-water two-phase flow behavior in ice heat storage systems

In this paper, we describe (1) the characteristics of ice-water two-phase flow created in a supercooling-type ice storage system, (2) the numerical analysis models for both processes of ice storing and melting within ice storage tanks, and (3) the design technologies for ice storage systems based on such predictive models, as well as the operational performance of actual equipment built with these design technologies. As the result of this technological development, it has been confirmed that the predictive approaches for the one dimensional ice accumulation in the given tanks and ice melting with low temperature water enough to air conditioning applications are reasonable and widely usable. Furthermore by the design conditions obtained here it is possible to simplify the construction of ice storage tanks and to realize high reliability in the actual equipment.     

煤气管道机器人远程信息交换系统的设计与实现

分析了煤气管道环境下远程信息交换系统的技术难点,提出了远程信息交换系统的设计方法和逻辑模型,建立了一种基于虚拟路由机制的信息交换规则,制订了相应的软、硬件设计和系统集成方案,最终实现了一种适合拖缆式煤气管道探测机器人作业特点和要求的远程信息交换系统.该系统采用分级信息交换、传输、处理模式,使用了特殊设计的光电混合电缆,信息数据传输时可兼顾能量的供给,通过实际煤气管道现场实验表明,该系统通信速率高,工作稳定,能有效地实现煤气管道机器人远程信息交换和控制.     

高可靠智能压力开关研发及应用

压力开关是火电机组保护系统中重要的一次信号元件,压力开关测量的准确性、可靠性及快速性直接决定了电厂保护系统能否正确、快速动作。针对机械式压力开关和压力变送器作为保护元件存在的不足,依据保护、调节、监视三分开控制系统设计原则,设计了微功耗、高可靠的两线制智能数显压力开关,并对智能压力开关进行可靠性设计和试验测试。测试结果表明,该压力开关有效地解决了传统压力开关存在的卡涩、偏移、不可监控和预测的问题,具有微功耗、高可靠、高精度和免校验等优点,为电厂保护系统的可靠运行提供了根本有效的保证。     

嵌入式网络化变电所电能量管理系统

 电能量管理系统是变电所自动化系统的重要组成部分．提出并研究设计了嵌入式网络化电能量管理系统,
以高性能嵌入式处理器和嵌入式实时操作系统为核心进行系统设计． 系统通过以太网口或嵌入式MODEM ,基于
TCP/IP协议进行网络通信,具有高可靠性、高实时性的特点．详细论述了系统设计、硬件设计和软件设计,并给出
实际运行结果．     

Reliability-based design optimization using a moment method and a kriging metamodel

Reliability-based design optimization (RBDO) has been used for optimizing engineering systems with uncertainties in design variables and system parameters. RBDO involves reliability analysis, which requires a large amount of computational effort, so it is important to select an efficient method for reliability analysis. Of the many methods for reliability analysis, a moment method, which is called the fourth moment method, is known to be less expensive for moderate size problems and requires neither iteration nor the computation of derivatives. Despite these advantages, previous research on RBDO has been mainly based on the first-order reliability method and relatively little attention has been paid to moment-based RBDO. This article considers difficulties in implementing the moment method into RBDO; they are solved using a kriging metamodel with an active constraint strategy. Three numerical examples are tested and the results show that the proposed method is efficient and accurate.     

采煤机螺旋滚筒振动可靠性分析

为研究某型采煤机螺旋滚筒振动可靠性,根据实际工况模拟螺旋滚筒的瞬时冲击载荷,建立螺旋滚筒的有限元模型,对其进行振动模态分析,识别出主要模态参数和振型规律,发现截齿部位振动变形明显;建立了螺旋滚筒共振失效准则,结合可靠性灵敏度分析理论和BP神经网络,得到了滚筒结构参数,振动可靠性灵敏度,分析结构参数对振动可靠性的影响。结果表明,螺旋滚筒振动可靠度为0.999549。基于共振失效准则,将协同仿真技术与BP神经网络和可靠性灵敏度分析理论相结合,为采煤机螺旋滚筒的振动特性分析与结构设计提供理论方法和数据支撑。     

Strategy and tool development for nuclear power plant design synthesis with measurement of reliability and simplicity

In this work, the conceptual design supporting tools for nuclear power plants have been developed. These tools are made for system synthesis, complexity measure and reliability analysis.This design synthesis program combined with the reliability analysis program accomplishes the system synthesis. This design strategy can reduce mistakes, effort and time. This design tool, based on Prolog language, is applied to the auxiliary feedwater system. A logic based fault tree analysis program (LOFT) is also developed using Prolog language. As LOFT performs symbolic computation during the fault tree analysis, linking with knowledge-base systems is very easy and the partial usage of the program is possible. The importance measure of components obtained from the system reliability analysis and the complexity measure of the system give very important information to the system designer.