地源热泵地埋管热短路问题的研究

地源热泵系统研究的重点和难点在于地埋管换热,归纳了影响地埋管换热诸多因素,认为受管内流体与土壤温差、管内流态、供回水管间距、回填材料导热系数、运行时间长短等因素影响,通过对单U地埋管换热性能的数值模拟,对比分析了保温地埋管、非保温地埋管、不同保温管长度及不同运行工况下换热情况,比较分析的结果表明,保温地埋管换热能力要高于非保温管,保温管长度要适宜,不同运行工况对地埋管进出口温差和换热量影响不同。     

垂直地埋管夏季非连续运行传热相干性数值模拟与研究

通过分析地埋管换热器的传热特性,建立了地源热泵地埋管换热器数学物理模型,利用FLUENT软件对换热器的传热相干性进行了数值模拟,在此基础上,通过对地埋管换热器传热性能实测与夏季非连续运行工况的模拟结果比较,得到不同埋管间距周围的土壤温度沿径向的变化规律及地埋管传热相干性的影响规律。     

地源热泵地埋管换热器换热性能研究北大核心CSCD

地埋管换热器的换热性能对地源热泵系统的整体性能具有重要影响,基于传热理论分析及CFD模拟,能够快速精确地分析地埋管换热器的换热性能,提高地源热泵系统方案设计的准确性。本文建立了地埋管换热器的有限长线热源模型,分析了单个地埋管换热器的温度变化情况及单位长度换热量;通过CFD模拟分析了四个单U型地埋管换热器组合的传热特性,得到换热器及土壤的温度场分布,并研究了土壤的温度恢复特性。     

土壤源热泵地埋管传热与机组性能的实验研究

在夏热冬冷地区的长沙建立了土壤源热泵系统实验台,开展了制冷工况下垂直U型地埋管换热器的实验研究,测定了地埋管周围的土壤热物性,分析了地埋管换热器的钻井深度、埋管类型、循环水流量等参数对地埋管传热和机组性能的影响。研究结果表明,选择合适的换热器类型、增大地埋管深度、提高循环水流量可以有效提高单位井深换热量。     

我国地源热泵规范中地下换热器的计算方法讨论

对国内外土壤源热泵地埋管换热器常用计算方法的对比进行了阐述,根据我国地源热泵系统工程技术规范(GB50366-2005)的地埋管换热器计算方法,对某实际工程在夏季工况下的地埋管长度进行了计算,并对计算中存在的几点问题进行了分析,就布置方式和地埋管的间距对地层热阻的影响得到了初步结论.     

垂直地埋管地源热泵地下环路模拟与分析

主要运用EnergyPlus系统模拟软件,对武汉某住宅垂直地埋管地源热泵地下环路进行系统模拟,分析垂直地埋管换热器设计的埋管深度与管内流量两个重要因素对热泵机组性能的影响,为垂直地埋管换热器设计提供有意义的参考。     

回填材料对地源热泵系统换热效率的影响分析

建立了区分岩土和回填区的地埋管换热器分区数值分析模型。采用数值分析手段分析了回填材料导热系数在不同地埋管间距、不同管径和不同埋管类型中的影响规律,对回填材料在地源热泵系统中的实际工程应用具有指导意义。     

土壤源热泵地埋管传热强化研究现状及其发展

分析了土壤源热泵技术特点及地埋管换热器的影响因素,指出地埋管换热器传热强化是地源热泵研究的核心问题之一,详细介绍了近十年来地埋管传热强化的国内外研究状况,在此基础上指出了土壤源热泵地埋管传热强化的最新进展和有待解决的关键问题。     

地下水流动对地埋管热作用距离影响的研究

地埋管换热器周围温度场随着运行时间变长不断向远处扩散,地下水流动使得埋管热作用距离沿流动方向大大增加。通过饱和含水层内地埋管换热模型,得到了地下水流动作用下埋管热作用距离的近似表达式,分析了地下水流速、土壤导热系数和孔隙率对热作用距离的影响。借助于地埋管热作用测试平台,分析了地下水流动作用下埋管热作用距离和热恢复特性,结果表明:地下水流动使得埋管热作用距离远大于纯导热模式,且热作用距离在埋管轴向不同埋深处大小不一,建议在地下水流速大于1×10-6m/s的地质区域,沿地下水流动方向设置埋管间距为8~10 m。     

污水管道工程开槽埋管技术分析

本文经过对开槽埋管施工图纸的细致分析,确定管道开槽施工方案,结合污水管道开槽埋管施工经验,对本工程有针对性地提出了开槽埋管施工方法。     

大庆石化总厂埋地输水管网阴极保护

通过对大庆石化总厂埋地输水管网沿线土壤、水质的测量与分析，确定埋地管网周围环境的腐蚀性，分析埋地钢管的腐蚀原因，并采用阴极保护的方法抑制埋地管线的腐蚀泄漏。     

重庆市埋地管道的腐蚀环境及阴极保护

对重庆市头玛线天然气埋地管道沿线的土壤进行了测量与分析 ,确定了其土壤环境的腐蚀性。采用单只阳极近距离埋设对阴极实施保护 ,管道全线保护电位稳定 ,保护效果良好。     

采用GIS-VRML技术的地下管网三维可视化与管理

以GIS为基础平台,VB为开发工具,采用组件开发模式,结合虚拟现实构造语言VRML,实现了地下管网的三维可视化与管理.介绍了管理系统的总体结构及其主要功能,详述了基于Web的地下管网三维虚拟显示的实现方法,为地下管线的三维数字化、网络化管理提供了一个实例.     

峰谷电价体制下东北输油管网日输油优化研究

东北原油长输管网是中国规模最大的地区性原油运输系统,就该管网基于峰谷电价体制下的运行现状,建立了线性规划数学模型,提出了日输油计划优化问题,并以铁秦线为例进行分析;初步揭示了峰谷电价体制下日输油计划方式的一些基本规律, 表明在该体制下东北管网具有一定的节能降耗潜力.但该方式在一定程度上受到管道本身运行特性的约束 ,与热油管道相比它更适合于等温管道.     

给水管道更新资金分配模型的研究

以管道更新前后管网维护费用 降低最大为目标,建立了考虑和不考虑 异型管两种情况下的管道更新资金分配 模型。实例验证了该模型能够在充分利 用维护资金的前提下,最大限度地降低 管网漏失损失,为供水管理部门合理使 用资金、有效控制漏损和产销差率提供 理论支持和决策指导     

Valid inequalities for the topology optimization problem in gas network design

One quarter of Europe’s energy demand is provided by natural gas distributed through a vast pipeline network covering the whole of Europe. At a cost of 1 million Euro per km extending the European pipeline network is already a multi-billion Euro business. Therefore, automatic planning tools that support the decision process are desired. Unfortunately, current mathematical methods are not capable of solving the arising network design problems due to their size and complexity. In this article, we will show how to apply optimization methods that can converge to a proven global optimal solution. By introducing a new class of valid inequalities that improve the relaxation of our mixed-integer nonlinear programming model, we are able to speed up the necessary computations substantially.     

武钢氧气公司综合管网信息系统的开发与应用

介绍武钢氧气公司现有供气管网系统存在的管理和维护困难等问题,以及综合管网信息系统的建立过程,阐述综合管网信息系统的实现功能及其测试情况,总结系统上线运行后的使用效果和存在的问题,并提出完善措施和改进方向。     

Fracture mechanics defect assessment diagram on pipe from steel P264GH with a notch

The design for a pipeline component is considered a tough challenge once defects in the base material develop. To address this issue, we present a gouge defect located in a pipe submitted to internal pressure. This problem is often encountered in the field of pipeline network and boiler components because of structural imperfection. To simulate the activity of such pressurized pipeline, a longitudinal cylindrical shell under pressure from a material of steel P264GH were involved in the research. Secondly, by this paper we propose a safety methodology to detect the boundary of failure assessment diagram (FAD), as a new solution to predict the service life of pipeline products. The methodology is connected to the modified FAD approach, whereas the specific parameters were settled using the Volumetric Method calculation, based on the notch Stress Intensity Factor, determined in the elasto-plastic field. This new modified FAD methodology entails an accurate solution, suitable to be used as expert tool for the assessment of workability and reliability of pipes network, in the case of corrosion defects presence.     

Bayesian Reliability of Gas Network Under Varying Incident Registration Criteria

Gas transmission pipeline network is of great importance to any country using natural gases in its various technological processes. However, the usefulness cannot overshadow the threat posed to people and property by the grid failures. In order to quantify the reliability of the grid, se veral widely recognized pipeline incident databases have been established. However, each database contains data about pipelines operated in remote geographical regions with varying soil types, under different incident registration criterion. For a longer time period even in single database, there is variation of these incident registration criteria. Therefore, analysis of an entire sample without regard to the incident criteria change raises suspicions about the validity of resulting inferences. Authors move beyond the qualitative pipeline incident database comparison and provide a methodology for quantitative integration of all available statistical information to improve gas pipeline network reliability evaluation. We develop a new model called Criteria‐dependent Poisson model, which takes into account various incident data collection criteria and extend it to the hierarchical (Bayesian) case when different databases with differing incident registration criteria can be joined in the same analysis. With the real data examples, we demonstrate the applicability of our method, which unfolds itself to be of great usefulness in reliability prediction. The Lithuanian pipeline network failure rate assessment shows the advantages of hierarchical structuring of Criteria‐dependent Poisson model in small sample problems. Copyright © 2015 John Wiley & Sons, Ltd.     

Cross-platform method for identifying candidate network biomarkers for prostate cancer

Discovering biomarkers using mass spectrometry (MS) and microarray expression profiles is a promising strategy in molecular diagnosis. Here, the authors proposed a new pipeline for biomarker discovery that integrates disease information for proteins and genes, expression profiles in both genomic and proteomic levels, and protein?protein interactions (PPIs) to discover high confidence network biomarkers. Using this pipeline, a total of 474 molecules (genes and proteins) related to prostate cancer were identified and a prostate-cancer-related network (PCRN) was derived from the integrative information. Thus, a set of candidate network biomarkers were identified from multiple expression profiles composed by eight microarray datasets and one proteomics dataset. The network biomarkers with PPIs can accurately distinguish the prostate patients from the normal ones, which potentially provide more reliable hits of biomarker candidates than conventional biomarker discovery methods.