入口含气率对深海多相混输泵性能影响研究

Investigation on the influence of inlet gas volume fraction on the performance of deep-sea multiphase pump

该文以标准状态下的水(连续相)和空气(离散相)作为流动介质,基于Eulerian-Eulerian非均相流模型,在不同进口含气率工况下对离心式深海多相混输泵内部流动特性进行数值模拟计算,研究离心式深海多相流混输泵的内部流动特性。通过获得叶轮和扩压器内部相态分布情况以及液相速度流线图,探索气液两相流在混输泵内部的流动规律。结果显示:气液两相工况下,混输泵从首级到末级的增压能力变化趋势相同,不同含气率下,末级混输泵的增压能力变化更大,含气率越高对增压能力影响越大;在低含气率下整个流道内的气相分布很均匀,气相更多聚集在叶片吸力面及出口边附近且有沿着叶片吸力面向叶轮出口运动的趋势,当进口含气率大于10%后,叶轮流道内叶片吸力面处出现较为明显的相态分离现象;不同含气率下叶轮和扩压器内压力脉动幅值变化趋势相似,幅值随着含气率的增加不断上升,通过实验结果验证了数值计算所采用的计算模型和方法是可靠的。

In this work,water(continuous phase)and air(discrete phase)in the standard state are used as the flow media.Based on the Eulerian-Eulerian inhomogeneous model,the numerical simulation of the centrifugal deep-sea multiphase mixed transport pump is carried out under different inlet gas volume fraction conditions,and internal flow characteristics of this pump are studied.By obtaining the phase distribution and the liquid velocity diagram in the impeller and diffuser,the flow law of gasliquid two-phase flow in the multiphase mixed transport pump is explored.The numerical results show that the variation tendency of pressurization capacity in the mixed transport pump is uniform from the first stage to the last stage under the gas-liquid two-phase condition,and the pressurization capacity of the last stage is more variable with different gas volume fraction conditions.The higher the inlet gas content,the greater the effect on the boosting capacity.The gas distribution of the impeller is uniform under the low gas content condition.Meanwhile,the gas phase aggregates on the blade suction surface and tends to move along the suction side towards the impeller outlet.As the inlet gas volume fraction is more than 10%,the separation phenomenon of phase state appears obviously at the blade suction surface in the impeller.The pressure pulsation amplitude variation trend is similar in the impeller and diffuser under different gas volume fraction,and the amplitude enhances with the increase of gas volume fraction.Finally,the experimental results verify that the model and method used in the numerical calculation are reliable.