In offshore oil and gas transport, gas-liquid mixed transport is a basic flow phenomenon. In general, pipeline undulations are caused by seabed topography; therefore, it is of great significance to study the mechanisms underlying gas and liquid flows in hilly-terrain pipeline-riser systems. This study established a hilly-terrain pipeline-riser experimental system in an indoor laboratory. The flow pattern and its flow mechanism were studied via experimental observation and pressure detection. Experimental results showed that the gas-liquid flow pattern in the hilly-terrain pipeline-riser system can be divided into four types: severe slugging, dual-peak slug, oscillation flow, and stable flow, where dual-peak slug flow is a special flow pattern in this pipeline system. Hilly-terrain units obstruct the downstream gas transport, weaken the gas-liquid eruption in the riser, and increase the cycle of severe slugging. In this paper, gas is regarded as power in the flow of gas and liquid, and the accumulation of liquid in low-lying areas is regarded as an obstacle. Then, the moment of gas-liquid blowout is studied as main research object, and the mechanism of flow pattern transformation is described in detail. This study investigated the accuracy of the OLGA 7.0 simulation results for the gas-liquid two-phase flow in the hilly-terrain pipeline-riser. The results show that OLGA 7.0 achieves a more accurate calculation of severe slugging and stable flow and can predict both the pressure trend and change characteristics. However, the simulation accuracies for dual-peak slug flow and oscillation flow are poor, and the sensitivity to gas changes is insufficient.

中文翻译：

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丘陵-地面管道提升管系统气液流动的实验与数值研究。

在海上油气运输中，气液混合运输是一种基本的流动现象。一般而言，管道起伏是由海床地形引起的。因此，研究丘陵地形管道冒口系统中气体和液体流动的机理具有重要意义。本研究在室内实验室建立了丘陵地带管道上升实验系统。通过实验观察和压力检测研究了流场及其流动机理。实验结果表明，丘陵地带立管系统中的气液流态可分为严重，双峰，振荡流和稳定流四种类型，其中双峰流是特殊的。该管道系统中的流动模式。丘陵地带的单位阻碍了下游的天然气运输，减弱立管中的气液喷发，并增加严重击打的周期。在本文中，气体被视为气体在液体和液体中的流动，而液体在低洼地区的积聚被视为障碍。然后，以气液喷涌时刻为主要研究对象，详细描述了流态转换的机理。这项研究调查了OLGA 7.0模拟结果对丘陵地形管道上升段中气液两相流的准确性。结果表明，OLGA 7.0可以更准确地计算出严重的团块和稳定的流量，并且可以预测压力趋势和变化特征。但是，双峰段塞流和振荡流的模拟精度较差，并且对气体变化的敏感性不足。