天然气液烃输送管道非平衡汽液相变及两相流动研究进展

天然气液烃(NGL)的主要成分是乙烷、丙烷、丁烷等低碳烷烃。在压力瞬变工况下,储运设备中的NGL汽液相变过程很难在瞬间达到热力学平衡状态,由此引发非平衡、非稳态的汽液两相流动。综述了NGL非平衡汽液相变机理及传热传质速率计算方法、非平衡汽液两相管流数学模型与数值模拟方法的研究进展。指出应着重开展以下三方面的研究:第一是采用实验和理论相结合的方法,探究NGL非平衡汽液相变的微观机理,建立汽液相间非稳态传热传质模型;第二是考虑非稳态传热传质过程与管道压力、温度、流速等参数之间的耦合作用,基于流体力学理论和非平衡态热力学理论,建立伴随非平衡汽液相变的NGL输送管道两相流动数学模型,研究模型的数值求解方法;第三是开发NGL输送管道仿真软件,揭示NGL汽液两相管流参数变化规律,为NGL输送管道的设计、运行和管理提供理论和技术支撑。

Research Progress on Non-equilibrium Two-phase Flow in Natural Gas Liquid Transmission Pipelines

The natural gas liquid (NGL) mainly is composed of light alkanes, such as ethane, propane, butane et al. In transmission pipelines, vapor-liquid change of the NGL cannot instantaneously reach the thermodynamic equilibrium state, which indicates the presence of the non-equilibrium and unsteady two-phase flow in pipelines. Research progress regarding the topics including mechanism of non-equilibrium vapor-liquid phase change, methods of predicting heat and mass transfer rates between vapor and liquid phases, and numerical simulation methods for the non-equilibrium two-phase pipe flow are reviewed. In the future, the following three aspects are suggested to be researched: (1) Use the experimental and theoretical methods to research the micro-mechanism of the vapor-liquid phase change, and to build corresponding unsteady state heat transfer and mass transfer models between vapor and liquid phases; (2) Build the numerical simulation model for the non-equilibrium two-phase pipe flow based on the fluid mechanical and non-equilibrium thermodynamic methods, and research numerical solution methods for the developed model; and (3) Develop the simulation software for NGL transmission pipelines, and use the developed software to predict the flowing parameters of two-phase NGL transmission pipelines. Achievements will contribute to improvements in the design, operating and management of NGL pipelines.