Abstract: The gas diffusion coefficient and therefore gasmixing section length was studied by using onedimension mathematical model in combination with three different methods for calculating gas diffusion coefficient (Taylor, TaylorCW and G.R.I). In addition, the predominant factors in affecting the gasmixing section length were also investigated, including pipeline length, diameter and velocity of the flow. And the comparison between the calculation results and field data show that TaylorCW method can reflect the field practice better. The relative errors of the results for three domestic pipelines are 397%, 23.4% and 22.0%, respectively.

Key words: Natural gas pipeline,    ,  Nitrogen gas replacement,    ,  Gasmixing section length,    ,  Data comparison

摘要： 基于一维混合模型研究天然气管道投产过程中气体的混合规律, 利用T a y l o r 、 T a y l o r 灢 CW、 G. R. I 3种不同方法分别计算出气体扩散系数及投产过程中形成的天然气 灢 氮气混气段长度, 分析了管道置换过程中影响混气长度的主要因素, 包括管长、 管径及流速。由T a y l o r 灢 CW 方法计算出的结果与现场数据最为接近, 用该方法验证国内3条已投产管道所得的相对误差分别为3 9. 7%、 2 3. 4%、 2 2. 0%。

关键词: 天然气管道,    ,  氮气隔离,    ,  混气长度,   ,  现场对比