【作者】 李军；

【导师】 玉建军；

【作者基本信息】 天津城市建设学院 ， 供热、供燃气、通风及空调工程， 2008， 硕士

【摘要】 随着国家“西气东输”二线工程的实施,我国的燃气管道建设又进入了一个新的高潮,更多的燃气管道相继投入建设和运行,为了保证这些管道的安全使用,将泄漏事故造成的危害降到最小程度,对燃气管道泄漏检测与定位技术的研究具有极其重大的现实意义和广阔的应用前景。管道泄漏检测是多领域、跨学科的课题,涉及到流体力学、传感技术、微弱信号检测、信号处理等多个学科,世界上对管道泄漏检测技术的研究已经有几十年的历史,但由于管道运行过程的复杂因素,使得至今没有一种权威通用并且简单可靠的泄漏检测办法。由于燃气具有易压缩、粘度低的特点,使得燃气管道的泄漏检测与定位就更加复杂。考虑到当今管网模拟的不断进步和燃气SCADA系统的日趋成熟,本文从提高泄漏检测的准确度和泄漏定位的精度两个方面来着手,着重研究了基于瞬态模拟的燃气管道泄漏检测与定位技术。为了提高燃气管道泄漏检测的灵敏度,本文通过理论分析不同的泄漏量和泄漏位置对管道流动参数的影响,得出了首末端压力比不同的燃气管道应测量不同的流动参数(压力或流量)来进行泄漏检测;引入了数理统计中假设检验的思想,构造了二元假设检验理论来提高泄漏检测的准确度。从模型的建立和求解两个方面着手来提高泄漏定位的精度。在稳态模型的建立上,利用流体力学三大方程(连续性方程、运动方程和能量方程),通过比较不同的状态方程选用了目前被认为最精确的用于天然气计量的BWRS状态方程,并以此方程为基础进行压缩因子、密度等热物性参数的计算;在稳态模型的求解上,选用容易计算,精度较高的标准型龙格—库塔(Runge-Kutta)法进行数值求解,并且在迭代过程的每一小步都重新计算燃气的压缩因子,摩阻系数等所有的计算参数,以减少数值计算的误差。更多还原

【Abstract】 Along with the second pipeline of“Transporting the natural gas from the west to the east project”implementations, China’s gas pipeline construction will enter a new upsurge, consecutively, more gas pipelines will put into construction and operation. In order to guarantee the safe operation of these pipelines and to minimize the hazards of gas pipeline leak accident, leak detection and location technology research is necessary, which also has extremely important practical significance and broad prospects.Pipeline leak detection is the multi-field, interdisciplinary topics related to fluid mechanics, sensing technology, weak signal detection, signal processing, and many other disciplines. The research to the pipeline leak detection has been several decades of history, but because of the complex process of pipeline operation, there has not an authoritative and reliable way to detect leakage. Being worth paying more attention is that, for gas has easily compressed and low-viscosity characteristics, making its pipeline leak detection and location is more difficult than any other pipeline. Taking into account the current continuous progress of pipeline network simulation and mature of gas SCANDA system, the paper researches gas pipeline leak detection and location technology based on transient simulation to improve the accuracy of leak detection and the precision of leakage position location.In order to improve the sensitivity of gas pipeline leak detection, the paper through theoretical analysis of different leakage quantity and different leakage position on the impact of pipeline flow parameters obtains that, different pressure ratio of the head to the end involves measure different flow parameters (pressure or flow) for leak detection. The paper also introduces the hypothesis testing ideas and constructs the binary hypothesis testing theory to improve the detection accuracy.From the establishment and calculation of the mathematical model two aspects to improve the precision of leakage position location. Establish the steady-state and transient model using the three hydrodynamics equations (Continuity equation, Momentum equation and Energy equation). By comparing different state equation, it selects the BWRS state equation which is considered the most accurate state equation in current natural gas measurement. It calculates compression factor, density and other Thermal parameters based on BWRS state equation. In Numerical solution of the steady-state and transient model, compression factor, friction coefficient and all the other Thermal parameters are recalculated in each small time step to reduce the numerical calculation error.更多还原