Energy Performance and Pressure Fluctuation of a Multiphase Pump with Different Gas Volume Fractions
Energy Performance and Pressure Fluctuation of a Multiphase Pump with Different Gas Volume Fractions
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DOI：
10.3390/en11051216
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发表时间：
2018-05
期刊：
影响因子：
3.2
通讯作者：
Jinsong Zhang;L. Tan
中科院分区：
文献类型：
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作者：
Jinsong Zhang;L. Tan
深海石油资源丰富，市场需求巨大，需要先进的石油开采技术。多相混输泵是石油开采中的关键技术，它可以同时输送油气，并具有较高的效率。采用网格生成和Navier-Stokes方程求解的数值方法，研究了气体体积分数对多相泵能量性能和压力波动的影响。实验结果与计算结果吻合较好，表明该数值方法能够准确地模拟泵内的多相流。泵的压力升随着流量的增加而减小，泵的效率随着气体体积与总体积之比的增加而减小。结果表明，叶轮和扩压器内压力脉动的主频分别为叶轮转速的11倍和3倍。由于水的密度和离心力较大，水聚集在护罩上，气体聚集在轮毂上，这使得GVF在泵中的分布不均匀。泄漏流在叶片吸力面前缘附近形成旋涡，进一步影响叶轮内的压力脉动。扩压器内明显的旋涡表明扩压器扩压器的扩压器角设计不合理，扩压器扩压比过大，容易引起气流分离。叶轮内均匀的流态表明该泵具有良好的水力性能。
Large petroleum resources in deep sea, and huge market demands for petroleum need advanced petroleum extraction technology. The multiphase pump, which can simultaneously transport oil and gas with considerable efficiency, has been a crucial technology in petroleum extraction. A numerical approach with mesh generation and a Navier-Stokes equation solution is employed to evaluate the effects of gas volume fraction on energy performance and pressure fluctuations of a multiphase pump. Good agreement of experimental and calculation results indicates that the numerical approach can accurately simulate the multiphase flow in pumps. The pressure rise of a pump decreases with the increasing of flow rate, and the pump efficiency decreases with the increasing of GVF (the ratio of the gas volume to the whole volume). Results show that the dominant frequencies of pressure fluctuation in the impeller and diffuser are eleven and three times those of the impeller rotational frequency, respectively. Due to the larger density of water and centrifugal forces, the water aggregates to the shroud and the gas gathers to the hub, which renders the distribution of GVF in the pump uneven. A vortex develops at the blade suction side, near the leading edge, induced by the leakage flow, and further affects the pressure fluctuation in the impeller. The obvious vortex in the diffuser indicates that the design of the divergence angle of the diffuser is not optimal, which induces flow separation due to large diffusion ratio. A uniform flow pattern in the impeller indicates good hydraulic performance of the pump.