对旋式轴流泵后置叶轮水力性能分析

Hydraulic performance analysis of rear impeller of counter-rotating axial flow pump

为了研究对旋式轴流泵后置叶轮对其水力性能的影响,采用CFD软件对该对旋式轴流泵装置进行数值模拟计算,将前置叶轮与后置叶轮水力特性进行对比分析,研究后置叶轮的进口安放角对整个装置水力特性的影响,最后通过模型试验验证数据的可靠性.结果表明:在设计工况下,对旋式轴流泵扬程为11.32 m,效率为87.57%.在小流量工况下,流量为300 L/s左右泵提前进入马鞍区,此时泵扬程为14.06 m,效率为79.48%;在大流量工况下,流量为440 L/s时,泵装置扬程为2.24 m,效率为54.16%.对旋泵后置叶轮的水流进口冲角要大于前置叶轮的水流进口冲角,导致后置叶轮叶片做功能力增强,后置叶轮扬程增大.改变后置叶轮安放角,特别在小流量工况下,后置叶轮的马鞍区同样提前,后置叶轮的进口液流角几乎相同.研究结果对于对旋式轴流泵后置叶轮的设计和优化提供参考依据.

In order to study the impact of the rear impeller on the hydraulic performance of the counter-rotating axial flow pump, CFD software was used to carry out numerical model calculation of the coun-ter-rotating axial flow pump device. Initially, the hydraulic performances of the front impeller and the rear impeller were compared and analyzed, and the influence of the inlet angle of the rear impeller on the hydraulic characteristics of the entire device was studied. Finally, the reliability of the data was verified through model tests. The results show that under the design conditions, the head of the coun-ter-rotating axial flow pump is 11.32 m, with an efficiency of 87.57%. Under low flow conditions, when the flow rate is about 300 L/s, it enters the saddle area in advance with a head of 14.06 m and an efficiency of 79.48%. Under high flow rate conditions, when the flow rate is 440 L/s, a head of 2.24 m with an efficiency of 54.16% is recorded. The flow inlet angle of the rear impeller of the coun-ter-rotating pump is greater than that of the front impeller, which leads to the enhancement of the wor-king ability of the rear impeller blades and the increase of the head of the rear impeller. By changing the placement angle of the rear impeller, especially under small flow conditions, the saddle area of the rear impeller is also advanced, and the inlet liquid flow angle of the rear impeller is almost the same. The research results provide a reference for the design and optimization of the rear impeller of the counter-rotating axial flow pump.