城镇天然气管道泄漏扩散的CFD模拟及后果分析

发布时间：2018-03-30 10:35

本文选题：城镇燃气　切入点：泄漏　出处：《重庆大学》2013年硕士论文

【摘要】：在天然气开发利用的飞速发展中，城市天然气输送管网越来越复杂。城镇天然气管道往往分布在人口和建筑集中的区域，这使得城镇天然气成为事故最频发、后果最严重的可燃可爆气体之一。掌握天然气泄漏扩散的规律可以对泄漏事故进行准确的预测、评价和控制，从而降低天然气管输事故的发生。本文建立了城镇天然气管道的泄漏扩散模型，从理论分析、CFD数值模拟、实验验证三个方面对其作了系统的研究。首先，利用流体力学基本理论分析天然气管道泄漏扩散的流动过程，建立气体流动基本控制方程；对气体紊流射流进行理论分析，建立天然气泄漏扩散的湍流模型；运用流体力学及工程热力学基本公式推导出三种泄漏模型：管道模型、管道—小孔综合模型、小孔模型以及对应的计算公式。利用Matlab数学软件编程计算出城镇高中压燃气管道可能会出现的泄漏事故下的泄漏量，汇总于表格中，为以后的研究提供参考；其次，由于湍流流动是一种高度非线性流动，流动状态比较复杂，，理论研究方法显然达不到要求，本论文通过理论分析并结合工程实际情况，建立城镇街道模式下天然气管道泄漏扩散的几何模型，利用CFD数值模拟软件对其进行模拟计算，对模拟结果进行分析，得出城镇高中压燃气管道泄漏扩散的一般规律。并用CFD模拟不同时间、不同管道压力、不同泄漏孔径以及不同障碍物条件下天然气的泄漏扩散状况，分析不同因素对天然气泄漏扩散的影响；最后，为了检验模拟数值模拟的合理性，利用相似性原理并结合燃气实验室实际情况建立实验模型并进行实验测量，将实验结果与模拟结果进行比较，得出实验结果与模拟结果在允许误差范围之内，证明了CFD数值模拟的正确性，说明利用k湍流模型对天然气管道泄漏扩散的模拟计算是可行的。
[Abstract]:With the rapid development of natural gas exploitation and utilization, urban natural gas pipeline network is becoming more and more complicated. Urban natural gas pipelines are often distributed in areas with concentrated population and buildings, which make urban natural gas become the most frequent accidents. One of the most serious combustible and explosive gases is to grasp the laws of natural gas leakage and diffusion, which can accurately predict, evaluate and control the leakage accidents, thus reducing the occurrence of natural gas pipeline accidents. In this paper, the leakage and diffusion model of urban natural gas pipeline is established, and the numerical simulation of CFD is analyzed theoretically, and three aspects of experimental verification are systematically studied. Firstly, the flow process of leakage and diffusion in natural gas pipeline is analyzed by the basic theory of hydrodynamics, and the basic governing equation of gas flow is established, and the turbulent flow model of natural gas leakage and diffusion is established by theoretical analysis of gas turbulent jet. Three kinds of leakage models are derived by using the basic formulas of hydrodynamics and engineering thermodynamics: pipeline model, pipe-hole synthesis model, The small hole model and the corresponding calculation formula. The leakage amount under the leakage accident that may occur in the town high pressure gas pipeline is calculated by using the Matlab mathematical software, which is summarized in the table, and provides the reference for the future research. Secondly, the turbulent flow is a highly nonlinear flow, the flow state is relatively complex, the theoretical research method obviously can not meet the requirements, this paper through theoretical analysis and combined with the actual engineering situation. The geometric model of leakage and diffusion of natural gas pipeline under the urban street mode is established, and the simulation results are analyzed by using CFD numerical simulation software. The general law of leakage and diffusion of medium and high pressure gas pipelines in cities and towns is obtained, and CFD is used to simulate the leakage and diffusion of natural gas under different time, different pressure, different leak aperture and different obstacles. The influence of different factors on the leakage and diffusion of natural gas is analyzed. Finally, in order to test the rationality of simulation numerical simulation, using the similarity principle and combining with the actual situation of gas laboratory, the experimental model is established and measured, and the experimental results are compared with the simulation results. The experimental results and the simulation results are within the allowable error range, which proves the correctness of the CFD numerical simulation, which shows that it is feasible to simulate the leakage and diffusion of natural gas pipeline by using k turbulence model.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU996.7

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