热力管网的拓扑优化

本文根据热力管网规划的概念及优化目标，提出了一种既实用又适于计算机处理的拓扑优化算法，并结合热力管理网设计的例子，给出了该算法的可行性论证以及优化计算结果。     

介质热力参数的编程计算方法

本文从实用的角度讨论热力工程的常用工质－水蒸气与燃气的热力参数的编程计算方法。     

浅谈热力站供暖系统循环水泵的选择方式

就城市集中供热工程中热力站供暖系统循环水泵的选择问题，对循环水泵的流量及扬程进行了分析计算，并对水泵台数的确定进行了阐述，最后介绍了水泵并联运行的特点，对提高供热效果，节约热能资源起到非常重要的作用。     

沼气热泵工质热力参数算法及软件设计研究

研究了制冷工质热力参数算法并应用线性插值的数学方法设计了制冷工质热力参数计算查询软件,该软件功能强大可以查询多种制冷工质的热力参数,另外还具有操作简单,使用方便等优点,可解决在制冷工程计算时查表不方便并且许多参数不能查到的问题,减少了工程的计算量,为工程计算人员提供了许多便利。     

地面辐射供暖系统热力工况分析与系统参数设计

从原理出发,对地面辐射供暖系统的热力工况进行全面分析,由热力工况结合JGJ142--2012《辐射供暖供冷技术规程》较JGJ142--2004《地面辐射供暖技术规程》的参数变化,研究在新标准下系统设计热负荷、管间距的设置参数,并给出系统供水温度调节公式的修正方法,为地面辐射供暖系统参数的设计提供参考建议。     

工业循环冷却水处理技术优化分析

随着我国市场经济的发展,工业企业也跟着迈上了新的台阶。但是,工业企业在生产过程中也对水资源造成了一定的污染和浪费。文章针对工业循环水的概述、工业循环冷却水的处理技术和相关的优化措施进行分析,希望对我国工业企业的发展有所启示。     

论热风热力参数对干燥速率的影响与干燥技术分类

分析了热风热力参数，即热风温度和含湿量对球形物料干燥速率的影响，绘制了三线四区的热风含湿量－热风温度图。该图表明，按热风热力参数，干燥技术可以分为低温、常温和高温高湿三大类，这些结论对干燥技术的分类，开发和应用具有普遍的理论与实践价值。     

电厂200MW机组热力系统运行热经济性分析研究

随着我国社会的不断进步,经济的飞速发展,作为影响国民经济的电力资源企业也在寻求和研究最好的生产技术。基于这种现状,本文通过对电厂的热力系统的热效率进行计算与研究,分析了主要影响热力系统经济性的因素及其计算偏差对机组热力系统运行的热经济性的影响,最后为机组热力系统的运行提供了合理化的建议及可控参数,使技术人员可根据运行参数能够准确的分析热耗,并对今后的热力系统的控制指明了方向。     

锚索框架梁的双参数法优化分析

采用双参数法分别分析了不同悬臂长度、跨距条件下弯矩极值随柔度特征值λ的变化规律。计算结果表明,基础梁的弯矩值并非由地基基床系数或梁的抗弯刚度单独决定,而是由柔度特征值λ决定;悬臂段长度与跨距的比值决定了梁端的弯曲方向,间接影响了梁的整体弯矩值;当柔度特征值λ较小,悬臂段长度与跨距的比值在0.32～0.35范围内时,随着λ减小,基础梁的弯矩变化幅度不大,即受λ影响较小,此时框架梁受力更加合理。     

两级吸收制冷循环中间压力对热力系数的影响

分析了两级吸收溴化锂制冷循环传统热力计算方法的不足，提出了通过计算中间压力来确定热力循环的方法以及中间压力的数学模型，获得了中间压力的优化计算模型。     

Exergy-based ecological optimal performance for a universal endoreversible thermodynamic cycle

Exergy-based ecological optimisation of a universal endoreversible thermodynamic cycle model is performed using finite time thermodynamics or entropy generation minimisation. The cycle consists of two constant thermal-capacity heating branches, a constant thermal-capacity cooling branch and two adiabatic branches. An ecological optimisation criterion is taken as the objective, which consists of maximising a function representing the best compromise between the power output and exergy loss rate of the heat engine. The analytical formulae for power, efficiency and ecological function of the universal endoreversible thermodynamic cycle with heat resistance loss are derived. The comparative performance analyses for Diesel, Otto, Atkinson, Brayton and Dual-cycles are carried out by a detailed numerical example, which show that the ecological criterion is more available.     

Exergetic analysis of closed Brayton thermal power cycle with reheater,regenerator and intercooler

Energy and exergy analysis of a Brayton cycle gas turbine power plant with regenerator, reheater and intercooler is carried out in this work. It has been found that the effects of the regenerator, intercooler and reheater are significant. Although, the energy analysis shows that the first law efficiency is more effective than the second law efficiency and there are significant losses in these components which cannot be neglected, and hence proper care should be taken for the size and operating conditions of these components. Efficiency of some components is 100% especially when energy balance is applied, while it is not 100% in the case of energy consuming/conversion systems like compressor, turbine, etc. The energy loss in reheater is zero while there is a small amount of exergy loss. The intrercooler has both energy and exery losses, so proper care should be taken in intercooler.     

带有控制参量的向量优化问题研究

在拓扑向量空间中,考虑了带有控制参量的向量优化问题.首先,给出了带有控制参量函数的广义凸概念,并在目标函数和约束函数的广义凸假设下,获得了问题的Benson真有效解与相应的标量化问题的最优解的关系.然后,定义了问题的实Lagrangian函数及Lagrangian函数的鞍点,并在目标函数和约束函数的广义凸假设下,推导了问题的Benson真有效解和鞍点的关系.     

A thermodynamic analysis of a transcritical cycle with refrigerant mixture R32/R290 for a small heat pump water heater

In this study, a thermodynamic analysis on the performance of a transcritical cycle using azeotropic refrigerant mixtures of R32/R290 with mass fraction of 70/30 has been performed. The main purpose of this study is to theoretically verify the possibility of applying the chosen refrigerant mixture in small heat pumps for high temperature water heating applications. Performance evaluation has been carried out for a simple azeotropic mixture R32/R290 transcritical cycle by varying evaporator temperature, outlet temperature of gas cooler and compressor discharge pressure. Furthermore, the effects of an internal heat exchanger on the transcritical R32/R290 cycle have been presented at different operating conditions. The results show that high heating coefficient of performance (COP_h) and volumetric heating capacity can be achieved by using this transcritical cycle. It is desirable to apply the chosen refrigerant mixture R32/R290 in small heat pump water heater for high temperature water heating applications, which may produce hot water with temperature up to 90 °C.     

Life-cycle optimization in the establishment of performance-acceptance parameters for seismic design

A life-cycle formulation is presented for the determination of optimum values of the mechanical properties of a structural system exposed to seismic risk. The resulting values are intended for providing support for the establishment of performance-acceptance criteria and parameters for seismic design. A method is developed for the determination of expected damage functions in terms of simplified reference models of the complex nonlinear systems that are typical of engineering practice. The uncertainties associated with the use of the simplified model to estimate peak dynamic responses of the system of interest are accounted for by means of first-order second-moment probabilistic criteria. An illustrative application of the criteria proposed is presented, together with a discussion about the translation of the results of the optimization studies into engineering criteria and methods expressed in conventional design formats.     

钻孔注水处理两器地基

从稳定、变形和强度三方面对地基土强风化岩的组分和特征进行了分析,提出了钻孔注水的地基处理方法。经过综合比较,得出钻孔注水方法在费用和周期上占有优势,从沉降观测结果看,此方法确实解决了两器地基不均匀沉降问题。     

日本农协的销售服务与启示

作为日本农协销售服务核心的共同销售机制实现了农产品销售的市场优势,这对保护小规模生产者利益、形成产地品牌发挥了积极作用。日本农协在地产地消的实践中对销售服务的改进顺应了市场需求,提高了自身的凝聚力。同样面临小生产和大市场矛盾的中国在农产品流通领域还缺乏相应的机制和实践,有必要以形成产地品牌和地方农业良性发展为目标,引导和鼓励实施共同销售合作组织的发育。     

振频法索力测量中采样参数优化研究

为提高振频法索力测量结果精度,对影响拉索振动频谱精度的数据采样参数进行优化研究。根据振频法的测量原理,分析得出频谱精度是影响索力测量精度的一个重要因素,进而分析了采样参数即采样率和采样长度分别对频谱精度的影响,以及采样参数两者之间的关系。在此基础上,兼顾测量实时性及有限的数据存储空间,提出数据采样参数设置的优化准则,提高了索力测量精度。对某斜拉桥的拉索进行现场对比测试,结果表明,按照参数优化准则合理设置的参数使得索力测量精度至少提高2倍,此准则具有较好的工程应用价值。     

Reliability based life cycle cost optimization for underground pipeline networks

The safety of underground pipelines is the primary focus of water and wastewater industry. Due to low visibility and lack of proper information regarding the condition of underground pipes, assessment and maintenance are frequently neglected until a disastrous failure occurs. The reduction of pipe thickness due to corrosion undermines the pipe resistance capacity which in turn reduces the factor of safety of the whole distribution system. Providing an acceptable level of service and overcoming practical difficulties, the concerned industry has to plan how to operate, maintain and renew (repair or replace) the system under the budget constraints. This paper is concerned with estimating reliability of non-pressure flexible underground pipes subjected to externally applied loading and material corrosion during the whole service life. The reliability with respect to time due to corrosion induced deflection, buckling, wall thrust, bending stress is estimated. Then the study is extended to determine intervention year for maintenance and to identify the most appropriate renewal solution by minimizing the risk of failure and whole life cycle cost using Genetic Algorithm (GA). An example is presented to validate the proposed method with a view to prevent unexpected failure of flexible pipes at the minimal cost by prioritizing maintenance based on failure severity and system reliability.