悬浮叶轮对旋涡泵内流特性及轴向力的影响研究

Effect of Floating Impeller on the Inner Flow Characteristics and Axial Force in Regenerative Flow Pump

设计三种进出口轴向间隙厚度不同的旋涡泵模型(C1J3、C1J1和C3J1),采用SST k-ω湍流模型对悬浮叶轮式旋涡泵内部流动进行数值模拟,计算叶轮悬浮在不同轴向位置时旋涡泵的外特性和全三维流场,探讨旋涡泵各部件的压力分布特点和质量交换机理,并进一步揭示悬浮叶轮所受轴向力的变化规律。结果表明,三个模型中泵壳流道和轴向间隙内的压力增长模式一致,均从流动发展区逐渐过渡到流动发展加速区再进入阻隔面区域。流动发展区内流体流动尚不稳定,发展加速区内叶轮和泵壳流道内流体的交换流动稳定而充分,而阻隔面区内压力剧烈变化以阻止液体泄漏。与轴向间隙厚度相同的泵模型C1J1相比,模型C1J3和C3J1的扬程和水力效率较低,且受叶轮偏离影响,叶轮和泵壳流道内流体的能量交换强度相对较弱,各部件内监测点的压力增速也较为缓慢。此外,叶轮所受轴向力与叶轮悬浮位置有关,且有偏向轴向间隙厚度较大方向的趋势。

Three regenerative flow pumps with floating impeller(RFP),different in the thickness of inlet/outlet axial clearance,are designed.The SST k-ωturbulence model is employed in the numerical simulation of RFP’s inner flow characteristics.The external characteristics and full three-dimensional flow field of RFP with the impeller floating in different axial positions are calculated.The pressure distribution characteristics in each component and mass exchange mechanism in RFP are discussed,and the varying rules of the axial force exerting on the floating impeller is further revealed.The results show that the growth pattern of pressure in pump channel and axial clearance are consistent in three pump models,where the fluid flows from the flow development region to flow acceleration region and then enters into the stripper region.The flow in development region is not stable,but in acceleration region,the exchange flow between the impeller and channel is stable and sufficient.Besides,in stripper region,the flow pressure changes rapidly to prevent the flow leakage.Compared with the pump model C1J1 taking equal clearance thickness,the head and hydraulic efficiency of pump models C1J3 and C3J1 are relatively lower.Under the effect of the impeller deviation,the intensity of energy exchange between the impeller and channel is weaker,and the pressure growth rate on the monitoring points of each component is comparatively slow.Additionally,the axial force of impeller is related to the impeller’s floating position,and the impeller tends to deviate to the direction with larger thickness of axial clearance.