【作者】 袁朝庆；

【导师】 张敏政； 孙建刚；

【作者基本信息】 中国地震局工程力学研究所 ， 防灾减灾工程及防护工程， 2008， 博士

【摘要】 热力管道属生命线工程,一旦发生破坏,将会对取暖和热力生产造成严重的影响,产生直接经济损失和不良社会影响。管道的泄漏,特别是微小泄漏,如能及时发现,将为管道的及时维修、保养提供科学的预测信息,以便预防大的泄漏发生。因此,对管道泄漏的检测研究具有极为重要的现实意义。热力管道泄漏时,泄漏出的热水与周围环境存在温度差,通过关键点处的光纤光栅温度传感器可感知温度变化,从而判断泄漏的发生。该项研究可为石油、天然气、热力等管道的泄漏检测提供一种新方法。在总结管道泄漏检测的研究现状和发展趋势的基础上,论文针对热力管道泄漏,进行了实验研究、理论分析和仿真计算,并结合实际工程应用,为建立管道泄漏光纤光栅温度监测系统提供了理论依据和应用经验。研究表明,这一系统可推进管道运行的现代化管理、减少故障判定时间、减小泄漏事故的经济损失及社会影响,并能够实现管网的终身功能监测。论文进行的研究工作如下:一、介绍了光纤光栅传感技术的特点、应用情况及光纤光栅的工作原理,分析了光纤光栅对应力和温度的敏感特性,叙述了光纤光栅的解调方法和光纤光栅组成准分布式系统的工作原理,阐述了光纤光栅温度传感系统检测热力管道泄漏的可行性。二、设计了检测埋地热力管道泄漏的室内实验装置,测试了实验模型泄漏前、后的埋地管道周围土壤温度场,研究了管道泄漏后热水的渗流和温度场的耦合,得到了热力管道周围土壤温度场的变化规律。实验表明可通过周围土壤温度场的变化判断热力管道的泄漏,实验结果为数值计算模型的建立及数值模拟提供了依据。三、根据前人的研究成果,给出了热力管道泄漏前土壤温度场的物理和数学模型,将土壤这一半无限大区域简化为有界的区域。泄漏前管道周围土壤温度场将作为管道泄漏后非稳态土壤温度场计算的初始条件。在此基础上,建立了热力管道发生点泄漏后的三维非稳态的管道周围土壤温度场的物理和数学模型,以及热力管道发生线泄漏后的二维非稳态管道周围土壤温度场的物理和数学模型,并给出了相应的边界条件。四、确立了数值仿真计算模型及具体的计算参数,应用Fluent软件进行了管道泄漏前、后的管道周围土壤温度场的实验室模型和某一实际供热工程的仿真计算。利用数值仿真对泄漏前、后管道周围非稳态土壤温度场的分布变化规律进行总结,建立了泄漏量与温度影响区域的关系,进行曲线拟合。与实验数据对比分析,仿真效果较好。五、结合光纤光栅温度传感系统在大庆市某段10公里长热力管道工程的实际应用,总结了泄漏监测系统的设计和施工经验,并为检验该监测系统的工程应用效果创造了条件。更多还原

【Abstract】 Thermal Pipeline is a lifeline. The production of heat supply will be seriously affected, direct economic losses and social affection will be caused by pipeline leakage. Scientific information to pipeline maintenance is provided by discovering pipeline leakage, especially tiny leakage, the serious leakage can be prevented. So there is crucial practical significance to study on leak detection to pipeline. The leakage can be determined by monitoring the change of temperature through optical fiber sensor if the leaking hot water and surroundings have different temperature. A new method is offered to pipeline leakage detection on petroleum, nature gas, heat supply, etc in this paper.On the summary of study condition and developing trend of pipeline leaking detection, experimental research, theoretical analysis and numerical simulation on thermal pipeline leakage are made in this paper. The theoretical basis and applying experience are offered by application to practical project. The research indicates that the system can advance the modern management on pipeline course, lessen the time on fault determination, prevent economic losses and social affection and realize the continual monitor to the pipeline.The main studies in the paper are follows:1. The characteristic of sensing technique of optical fiber grating, practice application and optical fiber grating working theory is introduced; the sensitivity characteristic of optical fiber grating with stress and temperature is analyzed; demodulation method of optical fiber grating and working theory of optical fiber grating distributed system is described; the feasibility of temperature sensor system of optical fiber grating applying to thermal pipeline leakage detection is expatiated.2. The in-house experimental devices for leak detection of buried thermal pipelines is established; the temperature field of the earth on experimental model before and after leakage of buried pipelines is tested; the seepage and temperature field coupled with the leakage of pipeline is researched, and the change of earth temperature field are mapped. The experiment indicates that the leakage of thermal pipeline can be determined through the change of earth temperature field, and the results provide the basis to numerical simulation.3. Physical and mathematical models of temperature field before the leakage of the thermal pipeline are provided basing on other achievements, and infinite earth distinct is simplified to finite distinct. The temperature field of earth before leakage is used as the initial condition on calculating the unsteady temperature field of earth after leakage.On the basis, the physical and mathematical models of unsteady temperature field around pipeline in three and two dimensions after point leakage are established and corresponding boundary condition is provided. 4. The model and parameter of numerical simulation is ascertained; software Fluent is applied to numerical simulation of the temperature field of earth around pipeline in both experimental model and practical project before and after pipeline leakage; a conclusion is made on the change of unsteady temperature field of earth before and after leakage according to the numerical simulation and the relationship between quantity of leakage and the district influenced by temperature is established. Curve imitation is done. After being compared with experimental statistics, the effect is acceptable.5. According to the practical application of temperature sensor system of optical fiber grating in 10km thermal pipeline in Daqing, the design and construction experience of leak detection system are summarized, and the application effect of the detection system is proved to be possible.更多还原