双叶片泵内压力脉动的数值模拟

为分析双叶片泵内压力脉动特点及其主要影响因素，采用RNG κ-ε模型对由叶轮水体、蜗壳水体及叶轮进口延伸段水体组成的三维计算区域进行3种不同工况下的非定常计算。通过分析计算模拟数据得出压力脉动时域图及频谱图，结果表明，双叶片泵内压力波动呈正弦周期性变化，进口处监测点压力波周期为其他监测点的2倍；压力脉动主要与泵内动静耦合作用有关，叶轮进口压力脉动主频等于叶轮的转频，叶轮与蜗壳耦合处及蜗壳出口压力脉动主频等于叶轮转频与叶片数的乘积，不同流量下同一监测点具有相同的主频，但其主频幅值不同，小流量下幅值最大，设计流量下幅值最小，叶轮与蜗壳耦合处压力脉动从隔舌处开始在叶轮旋转方向上逐渐衰退，所得结论对掌握双叶片泵内压力脉动产生的原理及其特性具有重要的指导意义。

Numerical simulation of pressure fluctuation in double-blade pump

In order to analyze the characteristics and the major influence factors of the pressure fluctuation in the double-blade pump, the RNG κ-ε turbulence model was applied and the fluid field in the impeller, volute casing and the inlet extended section of the impeller under three operating conditions was computed. Based on the analysis of simulation data, the time-domain spectrums and frequency spectrums of pressure fluctuation were obtained. It showed that: the pressure wave was a periodic sine one in the double-blade pump and the period at inlet was double than other parts. The pressure fluctuation was effected by the rotor-stator coupling. The dominant frequency of the inlet pressure fluctuation of impeller was approximately equal to the impeller passing frequency, and that in the impeller-volute casing coupling part, and the outlet of volute casing was equal to the product of impeller rotational frequency and number of blade. The dominant frequency at the same monitoring point was constant but with different amplitude in different flow rate, high amplitude in low flow rate and minimum in design rate. In the impeller-volute casing coupling, the pressure fluctuation will start to decline along the direction of impeller rotation from the tongue. The conclusion will provide an essential guide to master the principles and characters of the pressure fluctuation in the double-blade pump.