多相混输泵内气液两相流动的压力脉动特性

Pressure fluctuation characteristics of gas-liquid two-phase flow in multiphase pump

为了探究含气率对多相混输泵内部流场结构和压力脉动特性的影响规律,基于Standard k-ε湍流模型,应用计算流体动力学软件ANSYS CFX在进口含气率IGVF分别为5%,10%和15%时对多相混输泵内流场和压力脉动特性进行数值计算,进而分析和归纳多相混输泵内部流场结构、频域和压力脉动系数随含气率的变化规律.结果表明:含气率在超过一定范围时会削弱混输泵内的压力脉动,同时主频幅值对压力脉动的影响较大;在气液两相下动静干涉作用仍是引起混输泵内压力脉动的主要因素,与此同时叶轮和导叶内的主频分别是11倍和3倍转频,并且最大主频幅值和压力脉动系数均出现在动静交接面附近.该研究结果可为多相混输泵的结构优化、水力设计和疲劳分析提供一定参考.

To perform a thorough investigation into the effect of inlet gas void fraction(IGVF)on the flow structure and pressure fluctuation characteristics in multiphase axial-flow pump,the transient flow field and pressure fluctuation characteristics in a multiphase axial-flow pump were numerically simulated at 5%,10%and 15%IGVFs based on the standard k-εturbulence model by employing ANSYS CFX.Then,the variation rules of internal flow field structure,frequency domain characteristic,and pressure fluctuation coefficient with IGVFs were analyzed and summarized.The results show that when the IGVF exceeds a certain extent,the pressure fluctuation is weakened.Meanwhile,the dominant frequency amplitude has a significant effect on the pressure fluctuation.Under the gas-liquid two-phase condition,rotor-stator interaction is still the main cause for pressure fluctuation.Specially,the dominant frequencies of pressure fluctuation in the impeller and diffuser are 11 and 3 times of the impeller rotational frequency,respectively.Further,the maximum amplitude of the dominant frequency and pressure fluctuation coefficient appear near the rotor-stator interface.The research results can provide some references for structural optimization,hydraulic design and fatigue analysis of multiphase axial-flow pump.