【作者】 蔡明庆；

【导师】 刘学来；

【作者基本信息】 山东建筑大学 ， 热能工程， 2012， 硕士

【摘要】 近几年来,城市热力管网发展迅速,尤其是直埋管道敷设技术更是得到了广泛的应用。目前,我国正处于高速发展时期,而能源紧张却制约了经济的发展,因此节能减排已成为我国的长期基本国策。由于供热行业是用能大户,因而也是节能减排的重点对象。本文在分析热水集中供热管网国内外节能降耗研究现状的基础上,对热水集中供热管网的热桥效应及热桥效应的影响因素进行了研究。在此研究的基础上得出了适用于热水集中供热管网的热桥隔断措施,并对热桥隔断措施进行了有效性分析,为其实际应用提供了一定的理论基础。首先,本文对热水集中供热管网中存在的热桥效应的概念进行了明确,确定了热桥效应在热水集中供热管网不同布置形式中存在的位置。然后对热水集中供热管网热桥效应形成的原因进行了分析,并对影响热桥效应的因素做了初步的分析。分析了热桥效应对于整个热水供热管网系统的输送热损失方面的影响及管网稳定性方面的影响。其次,根据工程实例中采集的数据,建立了固定墩热桥效应的物理模型和数学模型,运用CFD技术中的固液耦合传热整场模拟方法,模拟了热水集中供热管网直埋供热管道固定墩处的热桥效应,并对影响固定墩处热桥效应的因素进行了逐个分析模拟。数值模拟结果表明：单个固定墩的散热量巨大,埋深1.5m,供热管道直径为DN800的典型固定墩的散热量为3057W,相比较于具有保温措施的管道来说具有很大的节能潜力；影响固定墩热桥效应的因素中,钢筋混凝土的导热系数和供回水的水温的影响显著,固定墩埋深、土壤表面对流换热系数的影响不显著。对于在建集中供热管网可以通过寻找能有效降低直埋供热管网固定墩处综合导热系数的办法即对固定墩处的管道进行保温,来降低固定墩的散热损失。再次,根据工程实例中采集的数据,建立了固定支架热桥效应的物理模型和数学模型,运用CFD技术中的固液耦合传热整场模拟方法,模拟了热水集中供热管网架空供热管道固定墩支架的热桥效应,并对影响固定支架处热桥效应的因素进行了逐个分析模拟。数值模拟结果表明：单个固定支架的散热量巨大,架空高度为3.5m,供热管道直径为DN800的典型固定支架的散热量为1175W,相比较于具有保温措施的管道来说具有很大的节能潜力；影响固定支架热桥效应的因素中,钢筋混凝土的导热系数和供回水的水温的影响显著,管道外表面对流换热系数的影响不显著。对于在建集中供热管网要想有效降低固定支架的散热量还得从有效降低钢筋混凝土的综合导热系数方面入手,寻找切实可行的保温措施。最后,对集中供热管网系统中的保温方法进行了总结,在此基础上确定了固定墩、固定支架保温措施及相应的保温材料。在确定保温措施后,利用数值模拟技术对固定墩、固定支架保温措施的隔热有效性和稳定性进行了研究。研究结果表明所选用的保温措施隔热效果明显、稳定性能满足管网稳定、安全运行的要求。并且结合具体的工程实例,分析了固定墩、固定支架散热量在整个管段散热量中所占的比例,研究了增加固定墩、固定支架保温措施后整个管段的散热损失量,即从管网实例分析固定墩、固定支架保温措施的有效性,进而推算出热水集中供热管网进一步节能的潜力,为集中供热管网保温工程提供理论支持,为集中供热管网进一步节能降耗提供理论依据。更多还原

【Abstract】 In recent years, the rapid development of urban heat pipe network, especially the buried pipe laying technology has been widely used. At present, China is in a rapid development period, the energy crisis has restricted the economic development, and energy conservation has become China’s long-term basic national policy. The heating industry is a key target for energy saving.This paper analyzes the hot water heating network energy consumption on the present situation of the research at home and abroad. We study the hot water of central heating pipelines thermal bridge effect and the influence factors of thermal bridge effect. On the basis of this study, we have come to cut off measures for centralized hot water heating pipe network of thermal bridges and analysis measures effectiveness to provide a theoretical basis for its practical application.Firstly, we determine the thermal bridge effect of hot water central heating pipe network, and given a hot water central heating pipe network the concept of the thermal bridge effect. We find out the effect of thermal bridges in the hot water to focus on the location of the different arrangement of the heating pipe network. And then analyze the reasons for the formation of the thermal bridge effect, and analyze the factors affecting the thermal bridge effect. We analyzed the impact of the thermal bridge effect of the heating pipe network system transmission heat loss and the pipe network stability.Secondly, according to data collected in the project example, we have established physical and mathematical models of the thermal bridge effect of the fixed pier. The application of CFD technology in the solid-liquid coupled heat transfer of the entire simulation method to simulate the hot water central heating pipe network buried heating pipe fixed pier at the thermal bridge effect, and to simulate the various factors affecting the fixed pier at the thermal bridge effect. The numerical results show that:great heat dissipation of a single fixed pier, a depth of1.5m, heating pipe diameter of DN800’s typical fixed pier of the heat loss of 3057W.The heat dissipation is enormous compared to the pipes with insulation measures. Among the factors affecting the fixed pier thermal bridge effect, the thermal conductivity of the reinforced concrete and the impact of the supply and return water temperature are significant. Central heating pipe network can reduce heat loss of the fixed pie by reducing the thermal conductivity at the fixed pier.Thirdly, according to data collected in the project example, we have established physical and mathematical models of the thermal bridge effect of the fixation. The application of CFD technology in the solid-liquid coupled heat transfer of the entire simulation method to simulate the thermal bridge effect of the mounting bracket on overhead hot water central heating pipe network.The numerical results show that:great heat dissipation of a single fixation, a height of3.5m, heating pipe diameter of DN800’s typical fixation of the heat loss of1175W. The heat dissipation is enormous compared to the pipes with insulation measures. Among the factors affecting the fixed pier thermal bridge effect, the thermal conductivity of the reinforced concrete and the impact of the supply and return water temperature are significant. Central heating pipe network can reduce heat loss of the fixation by reducing the thermal conductivity at the fixation.Finally, we summed up the insulation in the central heating pipe network system. We determined the fixed pier and mounting bracket insulation measures and the corresponding thermal insulation material. We simulated a fixed pier, mounting bracket insulation measures insulation effectiveness and stability. The results show that the insulation measures have good thermal insulation and stability. We use a specific project examples, and analysis of the proportion of the fixed pier and mounting bracket amount of heat loss in the entire tube of heat loss. Hot water central heating pipe network energy saving potential from the instance of the pipe network, and provide theoretical support for the central heating pipe network insulation works, to provide a theoretical basis for the central heating pipe network to further energy saving.更多还原