TVD/LW混合格式在天然气管线瞬变仿真中的应用  

Simulation of transients in natural gas pipelines using hybrid TVD/LW schemes

作　　者：龙学渊[1] 杨敏[1] 谢云杰[2] 罗云[1] 

机构地区：[1]重庆科技学院石油工程学院,重庆401331 [2]西南油气田分公司输气处,四川成都610213

出　　处：《化工学报》2009年第2期317-324,共8页CIESC Journal

摘　　要：描述天然气在管线中瞬变流动的数学模型为一个非线性双曲守恒律型的非齐次系统,应用时间分裂方法来处理双曲型模型中的非齐次项,对每一个时间步长,时间分裂算法将原来的非齐次双曲型守恒律组转化为一个齐次非线性双曲型守恒律模型和一个常微分方程(ODE)。应用显式5点二阶精度的TVD格式求解齐次非线性双曲型守恒律模型,结合具有2阶精度的3点Lax-Wendroff格式计算与边界点相邻节点(第2点,第N-1点)的物理量;并用特征线法处理管线入口和出口处的各类边界条件。通过下游阀门突然关闭的这种极端情况和一条实际天然气管线进行瞬变流动测试TVD/LW混合格式的模拟瞬变流动的有效性,模拟结果表明,TVD/LW混合格式能成功地模拟各物理量在瞬变过程中的真实情况。The mathematical model describing transients in natural gas pipelines constitutes a non- homogeneous system of non-linear hyperbolic conservation. The time splitting approach was adopted to solve this non-homogeneous hyperbolic model. At each time step, the non-homogeneous hyperbolic model was split into a homogeneous hyperbolic model and an ordinary differential equation operator. An explicit 5 point, second-order-accurate total variation diminishing （TVD） scheme together with the Lax-Wendroff scheme to treat the neighborhood nodes of boundary, was formulated to solve the homogeneous system of non-linear hyperbolic conservation. The method of characteristics （MOC） was used to treat the boundary conditions at the inlet and outlet of the pipeline. An extreme condition involving instantaneous closure of a downstream valve and a real long pipeline＇s transients were used to test the effectiveness of the hybrid schemes. The simulation results showed that the hybrid TVD/LW schemes could simulate real situation of the physical variables in a transient process successfully.

关 键 词：混合格式 双曲守恒律 天然气管线 瞬变流动 TVD格式 波动 

分 类 号：TE88[石油与天然气工程—油气储运工程]