Experiment on the Effect of Superficial Gas-Liquid Velocities on Slug Flow-Induced Vibration in an Inclined Sagged Riser
Experiment on the Effect of Superficial Gas-Liquid Velocities on Slug Flow-Induced Vibration in an Inclined Sagged Riser
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DOI：
10.1115/omae2020-18034
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发表时间：
2020-08
期刊：
影响因子：
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通讯作者：
B. Ma;N. Srinil;Hongjun Zhu;Yue Gao
中科院分区：
文献类型：
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作者：
B. Ma;N. Srinil;Hongjun Zhu;Yue Gao
通过柔性立管或管道输送的海底液-气流可能发展成包括段塞流在内的各种流型。本文对倾斜上升管段塞流诱发振动进行了实验研究。在空气-水实验回路中，采用一段硅胶悬链管进行了小尺度实验。注意放在表观气体和液体速度对SIV响应的影响。管道运动和流动模式都是使用非侵入式高速摄像机记录的。还通过两个压力传感器测量管道入口和出口处的压力变化。通过采用不同的表观气液速度比对SIV系统进行了测试。在较高的气液速度比下，不稳定段塞流的发生被捕获，导致大幅度的SIV。文中给出了立管响应和振荡频率随时间变化的实验结果以及相应的弹状流特性。根据气液表观速度，段塞流特性观察到显着变化。这需要间歇性SIV，其振幅和频率沿着隔水管跨度进行调制，从而发出潜在动态应力和疲劳相关问题的信号。在所有的实验情况下，立管的响应被发现是多模态和占主导地位的基本平面模式，而面外振动是可以忽略不计的。实验观察表明，两种流体的流动条件，段塞特性和管道动力学的关键相互关系。这一发现对提升管内多相流输送系统的设计具有一定的指导意义。
Subsea liquid-gas flows conveyed through a flexible riser or pipeline may develop into various flow patterns including slug flow. In this study, the slug flow-induced vibration (SIV) of an inclined sagged riser conveying upward air-water flows is experimentally investigated. A small-scale experiment is carried out in an air-water test loop with a section of a free-hanging catenary tube made of silica gel. Attention is placed on the effect of superficial gas and liquid velocities on SIV responses. Both pipe motions and flow patterns are recorded using non-intrusive high-speed cameras. Pressure variations are also measured at the pipe inlet and outlet by two pressure transducers. The SIV system is tested by employing different ratios of the superficial gas-liquid velocities. Occurrence of unstable slug flows is captured at the relatively high gas-to-liquid velocity ratios, leading to a large-amplitude SIV. Experimental results of the space-time varying riser responses and oscillation frequencies are reported together with the associated slug flow features. Depending on the gas-liquid superficial velocities, slug flow characteristics are observed to vary significantly. These entail an intermittent SIV with modulated amplitudes and frequencies along riser span, signalling a potential dynamic stress and fatigue-related concern. In all experimental cases, the riser responses are found to be multi-modal and dominated by the fundamental planar mode whereas an out-of-plane vibration is negligible. Experimental observations suggest the key interrelationships of the two-fluid flow conditions, the slug characteristics and the pipe dynamics. This finding is meaningful for a practical design of riser transporting internal multiphase flows.