Abstract: The characteristics of gas⁃liquid two⁃phase flow during the pigging process is helpful to the design and operation of the pipeline itself and the upstream and downstream equipment. In this paper, the multiphase flow simulation software OLGA is used to study the gas⁃liquid two⁃phase flow law during the process of natural gas pipeline pigging. The changes of key analysis pipeline such as flow pattern, pressure, liquid holdup, pigging velocity, fluid volume and other parameters. The results show that: the pigging process in the undulating terrain, the gas⁃liquid two⁃phase stratified flow, slug flow and annular flow pattern. The pressure at the entrance of the pipeline is the largest, and the pressure decreases gradually along with the pressure fluctuation; the overall speed of the pig is not fluctuating, the average speed is about 3.5~3.8 m/s. The maximum length of liquid slug in the process of pigging is 3 851.0 m. The liquid holdup is constantly changing, the maximum clear liquid is close to 300 m3. The research conclusion has certain practical significance to the pigging operation of the natural gas pipeline in the relief area.

Key words: Natural gas pipeline, Pigging process, Slug flow, Numerical simulation

摘要： 研究清管过程中气液两相流流动特征，有助于管线本身及上下游设备的设计和操作。因此，采用多相流瞬态模拟软件OLGA，对起伏地区天然气管线清管过程中气液两相流动规律进行了研究，重点分析了清管过程中的流型、压力、持液率、清管速度、积液量等参数的变化规律。结果表明，由于清管过程中地形起伏较大，气液两相流体出现了分层流、段塞流和环状流等3种流型；管道入口处压力最大，沿程压力逐渐减小，压力波动情况与流体持液量和地形有关；清管器速度总体上波动不大，平均速度为3.5～3.8 m/s；清管过程中出现的最大液塞段长度达到3 851.0 m；持液率不断变化，最大清出液量接近300 m3。研究结果对地形起伏地区天然气管线的清管作业具有一定的实际指导意义。

关键词: 天然气管线, 　清管过程, 　段塞流, 　数值模拟