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本文简要阐述了传统架空蒸汽管道存在的问题,探讨了新型架空蒸汽管道的结构组成,包括隔热型滑动(导向)管托、隔热型固定支座,以及预制保温架空蒸汽管道.并以北方某市工业园区架空蒸汽管网为例,探讨了预制保温架空蒸汽管道与隔热管托的实践应用. 相似文献
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《工业加热》2018,(6)
针对聚氨酯预制直埋保温管道散热损失开展实验与数值模拟研究。通过实验测试了聚氨酯预制直埋保温管道的散热损失,同时对输送介质温度、聚氨酯导热系数、土壤温度及其导热系数进行了测试,对影响聚氨酯预制直埋保温管散热损失的相关因素进行分析。并根据实验数据开展数值模拟研究,分析了不同条件对聚氨酯预制直埋保温管道散热损失的影响。研究结果表明:聚氨酯预制直埋保温管道散热损失随输送介质温度的升高而增加,保温管道周围土壤温度与保温管道径向距离成反比,聚氨酯保温材料导热系数对保温管道的散热损失影响较大,土壤导热系数在1.082-1.561 W/m·K时,土壤导热系数与保温管道散热损失成正比,但对保温管道散热损失产生影响较小。 相似文献
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通过对典型长期在役热力蒸汽管道保温材料导热系数和保温结构进行实地测量,并在此基础上进行数值建模,探究两种不同因素对热力蒸汽管道保温性能的影响机制。其中,保温材料导热系数通过现场采样并利用Hot Disk热常数分析仪进行实验测量,保温结构参数以结构偏心率和底部镂空夹层厚度为关键特征参数。研究结果表明,数值计算与实验测量的管道散热损失能够很好吻合,其保温性能恶化系数分别为1.65和1.64。进一步分析表明,对于所选取热力管道,保温材料导热系数、偏心和镂空结构对保温性能恶化所占比重分别为67.7%,13.8%和18.5%。 相似文献
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为研究保温管道不同保温材料在埋地敷设和架空敷设时的保温情况,通过Ansys软件建模计算架空管道和直埋管道在不同保温材料下运行前期和运行稳定后热损失随时间变化的情况,模型考虑了保温材料和土壤的比热容。数据结果表明:在管道运行初期,直埋管道和架空管道的热损失几乎一致,保温效果主要取决于保温材料的导热系数。当管道运行稳定在管壁周围形成一个稳定的温度场后直埋管道的保温效果稍好于架空管道的保温效果,且随着保温材料导热系数的增加,埋地管道的保温效果越明显。在管道架空敷设时,选用导热系数小的保温材料收益更高。 相似文献
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本文重点介绍了东北地区重型行业热力管网保温现状,并用传热公式和单位热损失指标两种方法计算了管网的散热损失。对建筑物供暖采用单位供暖,有效热指标和工业卫生标准规定的通风换气系数测试室内外温差计算采暖有效热的方法。计算出热网、建筑物采暖热效率。对各厂目前供热系统进行测试。并比较了各种系统的优缺点。指示集中供热优于分散供热。热水采暖比蒸汽采暖节约能源等等。给机械工厂热力管网及采暖节能提供了一份参考资料。 相似文献
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为探究泵站压力管道的不同布置形式对管道振动的影响,选取宁夏盐环定泵站工程二泵站#1压力管道为研究对象,建立基于流固耦合的泵站压力管道水流ALGOR数值模型,并采用DASP振动测试系统获取振动信号对模拟结果进行验证,分析压力管道水流流态对管道振动的激励特征并提出优化设计方案。结果表明,压力管道进水管处、支管总管相接处及总出水管处均有强烈的振动,但进水管的振动较出水总管振动更为强烈;减振优化设计方案中,调整支管距离对降低水流对管道振动的激励效果微弱,增大管径及改变总管走向对其效果较好,其中总管走向在2°~5°之间较佳,不仅能降低管道振动,而且能减少泵站能耗损失。研究结果可为高扬程泵站压力管道的优化设计提供理论依据。 相似文献
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Bo Yu Yi Wang Jinjun Zhang Xin Liu Zhengwei Zhang Kai Wang 《International Journal of Heat and Mass Transfer》2008,51(3-4):597-609
Numerical simulations are carried out to study the thermal impact of the cold products pipeline on the hot crude oil pipeline of the steady state. The pipelines studied are those used in the West Pipelines in China. The physical properties of North Xinjiang crude oil and those of 90# gasoline were used in this study. The effect of pipeline interval on the thermal impact is studied in details at various conditions. 相似文献
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A mathematical model has been developed to describe the energy behaviour of a hot oil being pumped through a thermally insulated pipeline. With this model, for each specified application, predictions can be made of the interrelated optimal pipe size and temperature distribution along the pipeline corresponding to which ensues the least overall steady-state rate of energy expenditure due to thermal and hydraulic losses. In particular, the evolved iterative computational technique has been applied to the design of long (>100 km) crude oil pipelines. It is also relatively simple to extend the presented analysis in order to determine the optimal numbers of reheating and booster pumping stations necessary along the pipeline for any specific application. 相似文献
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《International Journal of Pressure Vessels and Piping》1999,76(7):401-409
A neural network methodology is herein applied to numerically treat the sensitivity analysis problem of above-ground pipelines under static loading by taking into account the possibility of development of uplifting phenomena at the pipe–saddle interfaces. Assuming classical frictionless unilateral contact to mathematically describe the pipeline support conditions coupled by an appropriate finite element scheme, the discrete problem is put in the form of an inequality constrained quadratic optimization problem with respect to either displacements or stresses. In order to investigate the structural response and the stress states of the above-ground pipeline at hand with respect to the variation of critical design parameters which are the pipe thickness and the support conditions, the sensitivity analysis problem is formulated as a quadratic programming problem with the design parameters appearing in the quadratic term. The feasibility of using appropriately designed neural networks to model the complicated nonlinear relationship between the several input parameters associated with above-ground pipelines and their support conditions is thus demonstrated. 相似文献
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《International Journal of Hydrogen Energy》2023,48(49):18804-18815
The desire for sustainable development in various countries has increased the use of hydrogen energy. Considering cost and time savings, the introduction of hydrogen into existing natural gas pipelines is an excellent option, and the failure consequences of hydrogen blending in natural gas pipelines should be considered. In this study, a solid flame model is used to calculate the thermal radiation intensity of a hydrogen-blended natural gas jet fire. A method is proposed to modify the calculation of the view factor in the near field, and parameters such as the specific heat capacity and calorific value of pure gas are replaced by the parameters of the mixed gas. The data of the Thornton and modified models are compared with the experimental results, and the modified model result is found to be more accurate. Using the modified model, the variations in different hydrogen blending ratios, internal pressures, and pipe diameters with the safe separation distance of the thermal radiation intensity in a pipeline accident are investigated, and the relationships between them are analyzed. 相似文献
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《International Journal of Hydrogen Energy》2020,45(35):18010-18020
We are reporting in this study the hydrogen permeation in the lattice structure of a steel pipeline designed for natural gas transportation by investigating the influence of blending gaseous hydrogen into natural gas flow and resulted internal pressure values on the structural integrity of cracked pipes. The presence of cracks may provoke pipeline failure and hydrogen leakage. The auto-ignition of hydrogen leaks, although been small, leads to a flame difficult to be seen. The latter makes such a phenomenon extremely dangerous as explosions became very likely to happen. In this paper, a reliable method is presented that can be used to predict the acceptable defect in order to reduce risks caused by pipe failure due to hydrogen embrittlement. The presented model takes into account the synergistic effects of transient gas flow conditions in pipelines and hydrogen embrittlement of steel material due to pressurized hydrogen gas permeation. It is found that blending hydrogen gas into natural gas pipelines increases the internal load on the pipeline walls due to overpressure values that may be reached in a transient gas flow regime. Also, the interaction between transient hydrogen gas flow and embrittlement of API 5L X52 steel pipeline was investigated using Failure Assessment Diagram (FAD) and the results have shown that transient flow enhances pipeline failure due to hydrogen permeation. It was shown that hydrogen embrittlement of steel pipelines in contact with the hydrogen environment, together with the transient gas flow and significantly increased transient pressure values, also increases the probability of failure of a cracked pipeline. Such a situation threatens the integrity of high stress pipelines, especially under the real working conditions of hydrogen gas transportation. 相似文献
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蒸汽管网模拟优化技术应用 总被引:1,自引:0,他引:1
洛阳分公司蒸汽管网包括10MPa、3.5MPa、1.0MPa和0.3MPa共4个等级.其中3.5MPa和1.0MPa蒸汽管网是主要管网。两套管网均存在供汽结构不合理,管段散热损失大,管网保温材料老化及破损严重,管段外表面温发较高(在50℃以上,局部管段超过80℃)等问题。为此.根据3.5MPa和1.0MPa蒸汽管网平衡数据.作出流量平衡表.利用蒸汽管网模拟分析软件(SNAMER)建立蒸汽管网模型并进行离线模拟分析。根据模拟分析结果,提出增设一条蒸汽跨线,以提高1号汽轮机发电机入口压力和汽轮机输出功率;将热电站至化纤装置3.5MPa蒸汽母管管径改为DN500,以减少压降;将部分管线保温材料改为硅酸铝镁纤维,保护层材质改为镀锌铝皮.以减少散热损火。模拟结果显示,实施上述措施后,1号汽轮机发电机入口压力约提高0.3MPa,在耗汽量不变的情况下,输出功率可提高3%:3.5MPa年1.0MPa蒸汽管网总散热损失将分别下降24%和31%;若对部分管线进行改造,每年将节约费用500万元。 相似文献