轴流泵叶片安放角增大过渡过程特性

建立配置虹吸式出水流道的立式轴流泵几何模型, 提出轴流泵在运行中调节叶片安放角过程的三维非定常数值模拟方法, 采用动网格及网格重构技术实现叶片自转与其随叶轮公转的复合运动。选定 3 种调节规律进行数值模拟, 获得相关工作参数变化规律和内部流场变化情况。结果表明: 采用 3 种不同时间增大叶片安放角 2°, 机组流量增加 4.4% ~ 4.9% , 叶轮水力矩增加 5.1% ~ 5.9% , 叶轮进出口平面的测点静压波动范围较大; 在叶片安放角增大的过程中, 叶轮区域流态恶化、有涡核分布, 叶片吸力面出现分布不均匀的低压区域; 调节时间为 1 s 时, 叶轮进 出口平面测点静压及叶轮水力矩的波动范围要大于其他两种规律, 叶轮区域的涡核分布也要多于其他两种规律, 故在较短时间增大叶片安放角会增加叶轮区域的不稳定性。

Characteristics of transition process of increasing axial flow pump's blade angle

The geometric model of vertical axial flow pump with siphon outlet channel and the 3D unsteady numerical simulation method of blade angle adjusting process was developed, whiledy namic grid and grid reconstruction method was adopted to realize the blades rotation wit h the impeller in the compound movement. Three adjusting rules were selected for numerical simulation too btain the changing rules of relevant working parameters and internal flow field changes. The results showed that: the flow rate increased by 4.4% ~ 4.9% , and the impeller torque increased by 5.1% ~ 5.9% , when the blade angle was increased by 2°at three different times; the static pressure fluctuation range of the impeller inlet and outlet plane was found large; during the process, the flow pattern in the impeller region deteriorated, vortex cores were distributed in the impeller region and there were low-pressure regions with uneven distribution on the blade suction surface; when the opening time was adjusted 1 second, the fluctuation range of static pressure at the impellercs inlet and outlet plane and impeller torque and the distribution of vortex core in the impeller region was larger than the other two working conditions, therefore, increasing the blade angle in a short time will increase the instability of the impeller area.