The complex liquid film behaviors at flooding in an inclined pipe were investigated with computational fluid dynamic(CFD) approaches. The liquid film behaviors included the dynamic wave characteristics before flooding...The complex liquid film behaviors at flooding in an inclined pipe were investigated with computational fluid dynamic(CFD) approaches. The liquid film behaviors included the dynamic wave characteristics before flooding and the transition of flow pattern when flooding happened. The influences of the surface tension and liquid viscosity were specially analyzed. Comparisons of the calculated velocity at the onset of flooding with the available experimental results showed a good agreement. The calculations verify that the fluctuation frequency and the liquid film thickness are almost unaffected by the superficial gas velocity until the flooding is triggered due to the Kelvin–Helmholtz instability. When flooding triggered at the superficial liquid velocity larger than0.15 m·s-1, the interfacial wave developed to slug flow, while it developed to entrainment flow when it was smaller than 0.08 m·s-1. The interfacial waves were more easily torn into tiny droplets with smaller surface tension, eventually evolving into the mist flow. When the liquid viscosity increases, the liquid film has a thicker holdup with more intensive fluctuations, and more likely developed to the slug flow.展开更多
文摘目前大部分气井由于生产动力降低而成为低产气井。为了探究低产积液气井的井下流动状况,文中以气液两相瞬态流动为研究对象,基于某低产气井现场实验数据,利用Fluent模拟软件建立了管径为0.124 m,管长为10 m的二维垂直井模型,并采用VOF(Volume of Fluid)多相流模型追踪气液两相流动界面,对低产积液气井中气液两相流动参数的变化特征进行了数值模拟研究。实验通过设置不同积液高度、不同大小流速,动态模拟了低产气井的流动特征,得到了各相流型和持气率的分布情况,并进一步分析了持气率对流型的影响,建立了持气率与气相表观速度的数学模型。
基金Supported by the Major State Basic Research Development Program of China(2011CB706501)the National Natural Science Foundation of China(51276157)
文摘The complex liquid film behaviors at flooding in an inclined pipe were investigated with computational fluid dynamic(CFD) approaches. The liquid film behaviors included the dynamic wave characteristics before flooding and the transition of flow pattern when flooding happened. The influences of the surface tension and liquid viscosity were specially analyzed. Comparisons of the calculated velocity at the onset of flooding with the available experimental results showed a good agreement. The calculations verify that the fluctuation frequency and the liquid film thickness are almost unaffected by the superficial gas velocity until the flooding is triggered due to the Kelvin–Helmholtz instability. When flooding triggered at the superficial liquid velocity larger than0.15 m·s-1, the interfacial wave developed to slug flow, while it developed to entrainment flow when it was smaller than 0.08 m·s-1. The interfacial waves were more easily torn into tiny droplets with smaller surface tension, eventually evolving into the mist flow. When the liquid viscosity increases, the liquid film has a thicker holdup with more intensive fluctuations, and more likely developed to the slug flow.
