水动力段塞流激发的混合立管振动响应

VIBRATION RESPONSE OF A HYBRID RISER EXCITED BY THE HYDRODYNAMIC SLUG FLOW

海洋立管是输送海上油气至生产平台的关键装备,面临油气两相流诱导振动的风险。本文通过建立气液两相循环系统,开展了不同气液比水动力段塞流作用下的混合立管流致振动响应实验研究,采用高速摄像同步捕捉了管道振动位移及管内气液两相流动特征。实验发现:柔性跳接管平面内振幅及管内液塞长度随气液比的增大而增大,模态切换更为频繁。柔性跳接管的主导振动频率与长液塞流动频率和压力波动频率吻合。刚性立管的摆动频率也参与了柔性跳接管的振动,但其影响沿管轴方向不断衰减,且随气液比的增大而减弱。

Marine risers are the key components for transporting offshore oil and gas to production platforms,experiencing the potential risk of two-phase flow-induced vibration.Based on the established gas-liquid two-phase flow loop,the hydrodynamic slug-flow-induced vibration of a hybrid riser was experimentally investigated at different gas-liquid ratios.The non-intrusive measurement with high-speed cameras was employed to capture the response displacements as well as the internal two-phase flow.The experimental results indicate that the in-plane response amplitude and the length of the liquid slug increase with the gas-liquid ratio.Moreover,the mode switching becomes more frequent.The dominant vibration frequency of the flexible jumper coincides with the recurrence frequency of long liquid slug and the fluctuation frequency of pressure.The oscillation frequency of the rigid riser is observed in the vibration of the flexible jumper,but its influence is continuously attenuated along the jumper axis.Furthermore,the influence is weakened with the increase of gas-liquid ratio.