三级轴流式油气混输泵内流场压力脉动特性

为研究轴流式油气混输泵含气工况级间相互影响以及流道内压力脉动特性,应用Fluent软件数值模拟了三级油气混输泵在设计流量下的全流场瞬态,获得了混输泵内两相运动特征和流动部件内压力脉动情况,并分析了压力脉动时域和频域。结果表明,动静干涉是产生静压波动的主要因素,静压波动均值从入口到出口逐渐增大,级内动静交界处耦合作用较小,级间动静交界处耦合作用则较为明显。各级压缩单元叶轮进口均为脉动最剧烈的地方,距离叶轮进口越远,压力脉动幅值越小,在叶轮出口达到最小。在压缩单元内,流动方向的压力脉动主频幅值逐渐降低。首级叶轮出口、二级叶轮中间和出口以及末级叶轮中间位置压力脉动频率主要为2倍叶频,其他监测点压力脉动频率均为1倍叶频。气相对压力脉动频率影响较小,仅影响幅值。研究结果可为混输泵的结构优化设计及流动诱导振动控制提供参考。

Pressure Fluctuation Characteristics of Interior Flow in Three-stages Axial-flow Multiphase Pump

To analyze inter-stage interaction and pressure fluctuation characteristics with different gas volume fraction in a multiphase pump, numerical simulations of unsteady turbulent flow in a three-stage multiphase pump under design operating condition were carried out by Fluent software. Pressure fluctuations at monitoring point in compression stage passages were obtained and analyzed in time and frequently domains. The results show that the rotor-stator interaction both moving parts and static parts is the main causes for pressure fluctuation, and the average fluctuation of static pressure increase gradually from inlet to outlet. Moreover, the inter-stage interaction has a significant effect for pressure fluctuation than interior-stage. Maximum pressure fluctuation appeared at impeller inlet, and the more closer, the more severe will be; the domain frequency on first stage impeller outlet, middle and outlet of second stage impeller and middle of last stage impeller is double blade passaging frequency while the others is only one passaging frequency. Under different gas volume fraction, it has effects on amplitude but domain frequency keeps the same. These results provide a theoretical basis for further optimization design, performance improvement and experimental study of the transport pump.