基于AutoCAD的燃气管网水力计算软件开发

以AutoCAD为平台,采用AutoCAD Object ARX二次开发技术实现对燃气管网水力计算的数据自动化处理,包括建立管网节点和管段的拓扑关系、读取Excel表中的管网数据并显示到图中,以获得管网的可视化;采用C#语言,编制了中低压燃气管网水力计算软件。     

城市燃气管网水力计算软件的开发

以AutoCAD为平台,采用VB二次开发技术实现燃气管网管段节点坐标的读取,自动生成燃气管网水力计算图;采用VC＋＋可视化编程语言,编制了城市燃气管网水力计算软件。     

AutoCAD VB(VBA)二次开发在燃气管网水力计算中的应用

本文利用VB(VBA)语言对AutoCAD进行二次开发,实现了对燃气管网节点、管段的捕捉及相关信息的读取,并利用VC 6.0对数据进行处理,实现管线节点的自动编号,自动生成管网的拓扑结构,然后调用燃气管网水力计算程序对管网进行水力计算,减小了燃气管网水力计算的工作量,提高了工作效率.     

燃气管网水力计算及水力计算图的绘制

介绍了采用燃气管网节点法水力计算的数学模型,运用线性化法进行水力计算。用软件可形成户型和设计自留型水力计算图和计算超大型燃气管网。     

基于AUTOCAD的燃气管网水力计算和自动绘图系统的研究

介绍基于AutoCAD的燃气管网水力计算模型和自动绘图方法，并且利用VBA编程实现，达到工程图纸和水力计算完美结合，减少手工画图工作量。     

自动导入管网图的燃气管网水力计算程序开发

介绍了AutoCAD的DXF文件（图形交换文件）数据格式特点,利用DXF文件作为数据接口,为燃气管网水力计算程序开发了管网拓扑结构图自动导入功能。该方法可根据管道属性导入管网图,简化管道数据输入过程。通过实例进行了验证。     

燃气管网节点方程牛顿法数学模拟

根据图论及燃气流动的规律，建立了管网的水力计算数学模型，采用牛顿法进行线性化数值解，并编制了燃气管网的计算软件。该软件可用于燃气管网事故工况的模拟、系统中某些部分改造对整个系统影响的估计及管网设计方案的选择等。     

基于遗传算法的燃气管道阻力系数辨识研究

结合遗传算法与水力计算模型,将城市燃气管网的实际数据与阻力系数辨识后水力计算结果进行对比,以建立与实际情况相符的管网仿真系统。以某地3个气源枝状高压管网为例,将节点实测压力与阻力系数辨识后节点计算压力进行对比,结果表明辨识后的管网水力计算结果相对误差在工程设计的范围内。基于MATLAB图形用户界面GUI开发阻力系数辨识和水力计算软件。软件载入相应数据后,能够进行水力计算及阻力系数辨识,用户界面友好,操作方便,结果直观。     

燃气管网水力计算与实测数据的拟合

介绍了城市燃气管网水力计算中利用实测管网数据（特征节点的压力和流量）调整环流量分配的原理、方法和步骤,分析了该方法出现偏差的原因.     

燃气管网的邻接矩阵描述及相应的水力计算算法

介绍了用邻接矩阵描述燃气管网的方法和对应的水力计算算法，并总结了用邻接矩阵描述燃气管网方法的特点。     

YND系列混凝土防冻减水剂的研制与应用

本文介绍了YND系列混凝土防冻型减水剂的主要技术特点。该系列防冻剂与常用防冻剂和防冻减水剂相比,引入的K~+、Na~+量减少70％,基本上避免了因掺防冻剂而促进的碱-集料反应。     

道路混凝土抗渗及抗冻性能的研究

分析了道路混凝土抗渗及抗冻性能研究的意义,通过试验对普通混凝土、单掺粉煤灰、单掺硅灰及粉煤灰与硅灰复合的混凝土的抗冻和抗氯离子渗透性能进行了研究,得出了适量的硅灰与粉煤灰复合是获得抗冻及抗氯离子渗透性能较好的混凝土的有效途径。     

District heating system design for a university campus

İzmir Institute of Technology campus is in use since 2000 and still under development. At present, heating is provided by individual fuel boilers. On the other hand, the campus has a geothermal resource in its borders with a temperature of 33 °C. Because of this low geothermal fluid temperature; heat pump district heating system is considered for the campus. As an alternative, fuel boiler district heating system is studied. Each heating system is simulated using hourly outdoor temperature data. For the simulations, a control system with constant flow rate and variable return water temperature is used and the main control parameter is the indoor temperature. Various heating regime alternatives have been studied for heat pump district heating system for the various condenser outlet temperature and geothermal fluid flow rate, and two of these alternatives are given in this study. Furthermore, economic analysis has also been done for each heating system alternative based on investment and operational costs. Results indicate that heat pump district heating system has the highest investment but lowest operational cost.The alternatives are evaluated according to internal rate of return method, which shows the profit of the investment and resulted that, the heat pump district heating system has minimum 3.02% profit comparing with the fuel boiler district heating system at the end of the 20-year period.     

掺硅烷乳液制备整体防水混凝土的抗冻性试验研究

进行了掺硅烷乳液制备整体防水混凝土的水冻、盐冻以及不同冻融损伤后的毛细吸水试验。结果表明,在混凝土拌合料中掺加一定量的硅烷乳液,使混凝土的抗冻性降低,并且随着硅烷掺量增加,混凝土的抗冻性能变差。但是在不同的冻融损伤条件下,掺硅烷制备整体防水混凝土仍具有较好的抵抗水分侵入性能。     

Theoretical performance of an adsorbed natural gas storage system subjected to variable charge–discharge conditions

A transient heat and mass transfer model is developed to simulate the performance of an adsorbed natural gas (ANG) storage system subjected to variable charge and discharge conditions. The obtained results are applicable for internal combustion engines with natural gas as the fuel. The ANG system performance is presented in terms of delivery capacity. Results are obtained for the cases of (i) constant pressure charging with a constant flow discharging and (ii) constant flow charging and discharging. Results show the importance of improving the heat transfer performance of the reactor, particularly at high specific gas flow rates. From the second law analysis of the system, it is seen that significant internal entropy generation occurs at high specific flow rate and low heating fluid temperatures. Based on the minimum specific entropy generation criterion, the optimum heating fluid temperatures for different ranges of specific flow rate of the adsorbate are found.     

Energy and exergy analysis of geothermal district heating systems: an application

In this study we present an energy and exergy assessment and modeling of geothermal district heating systems for their system analysis, performance evaluation and optimization. A comprehensive case study is conducted in Balcova geothermal district heating system (BGDHS) in Izmir, Turkey and actual thermal data are collected and employed for analysis. Using actual system data, an assessment of the district heating system performance, energy and exergy efficiencies, and exergy destructions in the system is conducted in this regard. The exergy destructions in the overall BGDHS are quantified and illustrated using exergy flow diagram. Furthermore, both energy and exergy flow diagrams are exhibited for comparison purposes. It is observed through analysis that the exergy destructions in the system particularly take place as the exergy of the fluid lost in the pumps, the heat exchanger losses, the exergy of the thermal water (geothermal fluid) reinjected and the natural direct discharge (hot water distribution losses) of the system, accounting for 1.64%, 8.57%, 14.84% and 28.96%, respectively, of the total exergy input to the BGDHS. For system performance analysis and improvement, both energy and exergy efficiencies of the overall BGDHS are investigated and are determined to be 41.9% and 46%, respectively.     

Model of a solar-assisted heat-pump system for space heating integrating a thermal energy storage unit

Details about a model developed to analyze a complex space heating system are given. Solar air heaters provide thermal energy for driving a vapor compression heat-pump and for other purposes. A (sensible heat) thermal energy storage (TES) unit ensures a more efficient usage of the collected solar energy. The TES operation is described by two non-linear coupled partial differential equations for the temperature of storage medium and heat transfer fluid, respectively. The two main operating modes of the space heating system are presented. The electric power required by the motor of heat-pump’s compressor is lower in case of the space heating system that includes a TES unit as compared to the simple solar-assisted heat-pump system. The saving in electric energy varies between 20–35% (during the months when the TES unit is uncharged) and more than 50% (for the months when the TES unit is charged).     

热源面积对室内热压自然通风的影响

针对具有内热源的民用建筑,采用计算流体力学(CFD)方法,通过改变热源面积对热压自然通风流场进行数值模拟分析,得出了不同热源面积下的通风量、排风温度及其变化规律,分析了不同工况下的温度场和速度场,得出了中和面高度和有效热量系数随热源面积的变化规律。结果表明:热源面积的变化主要影响房间下部的温度场,对通风量和排风温度的影响不大,对中和面高度和有效热量系数均有一定的影响。该结论为民用建筑自然通风系统的设计提供了理论依据。     

低温地板辐射采暖的分析

低温地板辐射采暖,用交联聚乙烯管(XLPE)、聚丁烯管(PB)等新型建材布置在楼(地)面结构层形成闭路盘管.它利用辐射原理与流体因加热上升的原理,保证人体活动空间的温度要求.地板辐射采暖节能,舒适,不占房间有效面积.此技术在发达国家已得到比较广泛的应用.随着人们对生活环境舒适程度要求的提高,近些年来低温地板辐射采暖在我国有较快的发展.     

Thermal feed-back as the way to reach higher and lower temperature potential in low energy processes

In this paper, thermal feed-back (TFB) as the way to reach lower and higher temperatures, is analysed. By definition, in TFB application one part of the fluid passing through the system is backed by feed-back connection from outlet to inlet, exchanging the heat flux with incoming fluid flow. The effect of TFB is analysed in two cases: (1) fluid heating and (2) air cooling by adiabatic humidification. In both cases, the TFB moves temperature limits of fluid at exit beyond the limits that are possible in standard installations. The global effect of TFB could be defined as some kind of transition “from quantity to quality”.