高压大直径天然气-凝析液管流计算模型

Modeling of gas-condensate flow in high pressure and large diameter pipelines

前人提出的平界面和曲界面模型大多是基于低压、小管径、水平或接近水平管道空气-水条件的实验数据得来的,如何选择长距离、高压、大直径、起伏地形天然气-凝析液管道水力计算模型是一个需要研究的问题。针对高压、大直径、起伏地形条件下的天然气-凝析液混输管线,运用相态与物性、水力、热力耦合的计算方法对分离流的气-液平界面和曲界面机理模型进行了适用性比较研究。将平界面和曲界面模型下的几何关系和摩阻系数计算相关式运用于实际的高压天然气-凝析液长距离地形起伏管道中,对比水力热力计算结果与实际生产数据,认为平界面模型较曲界面模型能更准确地预测高压、大直径天然气-凝析液两相流管线的压降和积液量。

The flat and curved interface models for gas-liquid separated flows in pipes are developed mostly from air-water flow experiments in low pressure,small diameter,horizontal or nearly horizontal pipes,which may not be suitable for high pressure,large diameter and undulating natural-gas-condensate pipelines.By use of methods for phase behavior and physical properties and coupled thermo-hydraulic computations,the suitability of these two mechanistic separated flow models to gas-condensate flow in long-distance,high-pressure,large-diameter and undulating pipelines was studied.Different combinations of friction factor correlations for the flat and curved interface models were embedded in thermo-hydraulic computations of an actual high-pressure,large-diameter,undulating natural-gas-condensate long-distance pipeline.The computational results of pressure drops and accumulated liquid contents for the flat gas-liquid interface model in this study agreed better with the field operating data than the curved interface model.