气液两相流管道弯头处脉动流激力特性研究

Investigation on characteristics of pulsating excitation force at elbow of gas-liquid two-phase flow pipeline

为了揭示管内两相介质流经弯头处引起的脉动流激力的特性规律,文中基于流体体积多相流模型和Realizable k-ε湍流模型,采用ICEM和FLUENT开发90°弯管两相流动三维数值计算模型,求得在塞状流型下,不同气液相表观流速和弯管结构下脉动流激力的时、频域曲线及截面含气率数据。计算结果表明:段塞流下弯头处流激力的主频范围在5—40 Hz内,流激力幅值与基频和液相表观流速呈正相关,与气相表观流速呈负相关;相比小曲率半径弯头,大曲率半径的弯头能够降低脉动流激力能量的集中程度,避免管道系统产生共振,从而保障工业管道在两相流工况下的安全服役。

In order to reveal the characteristic law of the pulsating flow exciting force caused by the two-phase medium in the pipe flowing through the elbow,a 3D numerical calculation model of the two-phase flow in a 90°elbow was developed based on the fluid volume multiphase flow model and the Realizable k-εturbulence model,and the ICEM and FLUENT calculation software were adopted.Under the plug flow pattern,the time-frequency domain curve and cross-section gas holdup data of the pulsating flow excitation force were obtained.And these data were derived from different gas-liquid phase apparent velocity and elbow structure.The results show that the main frequency of the pulsating excitation force at the elbow is within 5-40 Hz under the state of slug flow.The magnitude and fundamental frequency of the pulsating excitation force are positively related to the liquid superficial velocity,and inversely proportional to the gas superficial velocity.Compared with small elbows,elbows with large curvature radius can reduce the concentration of pulsating excitation force energy,and avoid the resonance of the pipeline system to ensure the safe service of industrial pipelines under two-phase flow conditions.