多级潜水电泵非定常流动数值模拟及性能预测

Numerical simulation and performance prediction of unsteady flow in multi-stage submersible centrifugal pump

为了研究多级潜水电泵内部流动特性,选取QD3-60/4-1.1首级叶轮和导叶为研究对象,采用修正的RNG k-ε湍流模型和滑移网格技术数值计算了泵三维非定常流场,给出了流道1中不同半径处相对速度液流角,绝对速度液流角和相对速度与圆周速度比值的分布曲线,分析了定常和非定常流道1出口压力面的速度三角形变化,并对扬程和功率的数值计算结果与试验结果进行了对比分析.结果表明:定常计算中随着流量的增加,叶轮出口绝对速度减小,绝对速度圆周分量减小,绝对速度径向分量增加;非定常计算中在0.90R2和0.95R2处靠近吸力面的相对速度液流角变化较明显,小流量工况下相对速度液流角一直在正负之间剧烈波动,绝对速度液流角随着流量的增大而增大;非定常计算可以较准确预测多级潜水电泵的特性.

To investigate the internal characteristics of flow field in multi-stage submersible centrifugal pump, the first stage of the pump with impeller and diffuser was selected. The three dimensional unstea- dy flow field of impeller and diffuser was simulated with RNG k-e turbulence model and sliding mesh technology. The relative velocity flow angle, the absolute velocity flow angle and the ratio of relative ve- locity and circumferential velocity at different radius in the first channel were obtained to analyze the ve- locity triangles of impeller pressure surface. The performance curves of numerical simulation were com- pared with the experiment results. The results show that the absolute velocity and the absolute velocity component are decreased with the increasing of flow rate. At the positions of 0.90R2 and 0.95R2, the changes of relative flow angle at 100% flow rate and at small flow rate are obvious. Unsteady calculation can accurately predict the performance of multi-stage submersible centrifugal pump.