天然气管网特征线法动态仿真分析

发布时间：2018-11-28 14:46

【摘要】：天然气与煤炭、石油等能源相比,具有无废渣废水、热值高、安全性好、清洁度高等优势,所以在发展低碳经济的时代背景下,天然气的使用备受青睐。管道作为天然气的主要运输方式,正朝着长距离、大口径、高压力和网络化的方向发展,逐渐形成了大型、复杂的供气系统。由于天然气管网系统日趋大型化和复杂化,增加了人们准确了解和掌握其运行规律的难度,限制了天然气管网优化方案的制定,使对天然气管网系统突发工况的分析和处理变得更加困难,并严重阻碍了天然气管网系统的合理规划设计、安全调度管理以及精确操作控制。所以,为了准确研究大型复杂天然气管网系统,天然气管网仿真技术应运而生。它揭示了在不同设计、调度和操作方案下,天然气管网内的流动工艺和水力、热力分布,描述不同操作、变化和事故条件下的水力、热力变化趋势和过程,是天然气管网实施各种决策方案的支撑技术。因此,本文的研究对天然气管网的优化设计、有效管理、合理调度、可靠运行具有重要意义。本文调研了大量国内外文献,紧跟国内外天然气管网动态仿真的研究成果,对天然气管网特征线法动态仿真进行了分析。首先,针对目前天然气管网动态仿真过程中忽略对流项、惯性项和中立项等问题,本文基于适用任意流体的连续性方程、动量方程、能量方程,结合真实气体的状态方程以及焓方程,建立了具有普遍适用性的天然气管道动态仿真数学模型;其次,采用BWRS气体状态方程,通过抛物线法迭代求解,大幅度提高了气体状态参数的计算速度和精度,并编制了气体物性包程序,为管网动态仿真计算奠定了基础;选取适用范围广、精度高的Colebrook公式,并采用弦截法计算管道摩阻系数,将摩阻系数与管道流量关联起来,从而减小了摩阻系数因定值输入产生的误差;再次,引入黎曼不变量n和m,以及微分算子S、M和N,建立了天然气管网特征线法动态仿真状态空间模型,并结合初始条件和边界条件,通过逆步进法和线性内插值法对管网动态仿真模型进行求解,使得求解过程的实现更加便利;最后,以C++Builder XE6.0为开发平台,采用C++语言对天然气管网动态仿真过程进行编程,并通过天然气管网实例检验本文提出的特征线法动态仿真分析的可行性。结果证明了特征线法动态仿真具有良好的仿真效果,可以为天然气管网的规划、设计、调度、控制和管理等各个层次的应用提供可靠的依据。
[Abstract]:Compared with coal, petroleum and other energy sources, natural gas has advantages of high calorific value, good safety and high cleanliness, so the use of natural gas is favored under the background of developing low carbon economy. As the main transportation mode of natural gas, pipeline is developing towards the direction of long distance, large caliber, high pressure and network, and has gradually formed a large and complex gas supply system. Because the natural gas network system is becoming larger and more complicated, it makes it more difficult for people to understand and master its operation law accurately, which limits the formulation of the optimization scheme of natural gas pipeline network. It is more difficult to analyze and deal with the sudden condition of the natural gas pipeline network system, and it seriously hinders the reasonable planning and design, the safety dispatching management and the precise operation control of the natural gas pipe network system. Therefore, in order to accurately study the large complex natural gas network system, the simulation technology of natural gas pipe network came into being. It reveals the flow process, hydraulic and thermal distribution in the natural gas pipe network under different design, scheduling and operation schemes, and describes the trends and processes of hydraulic and thermal changes under different operation, variation and accident conditions. Is the natural gas pipe network implementation of various decision-making support technology. Therefore, the study of this paper is of great significance to the optimization design, effective management, reasonable scheduling and reliable operation of natural gas network. In this paper, a large number of domestic and foreign literatures have been investigated, and the dynamic simulation of natural gas pipeline network characteristic line method has been analyzed by following the research results of natural gas network dynamic simulation at home and abroad. First of all, aiming at the problems of neglecting the convection term, inertia term and neutral term in the dynamic simulation of natural gas network, this paper bases on the continuity equation, momentum equation and energy equation applicable to any fluid. Combined with the state equation and enthalpy equation of real gas, the dynamic simulation mathematical model of natural gas pipeline with universal applicability is established. Secondly, the calculation speed and precision of gas state parameters are improved greatly by using BWRS gas state equation and parabola method, and the gas physical property package program is compiled, which lays a foundation for the dynamic simulation calculation of pipe network. The Colebrook formula with wide application range and high precision is selected, and the friction coefficient of pipeline is calculated by using the chord section method, and the friction coefficient is correlated with the flow rate of the pipeline, thus reducing the error caused by the constant value input of the friction coefficient. Thirdly, by introducing Riemannian invariants n and m, and differential operators Schim and N, the dynamic simulation state space model of natural gas pipeline network characteristic line method is established, and the initial conditions and boundary conditions are combined. The inverse step method and linear interpolation method are used to solve the dynamic simulation model of pipeline network, which makes the solution process more convenient. Finally, using C Builder XE6.0 as the development platform, C language is used to program the dynamic simulation process of natural gas pipeline network, and the feasibility of the dynamic simulation analysis of the characteristic line method proposed in this paper is verified by an example of the natural gas pipeline network. The results show that the feature line method has a good simulation effect and can provide reliable basis for the application of natural gas network planning, design, scheduling, control and management.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE832

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