旋流泵内部流场压力脉动特性数值分析

Numerical analysis of pressure fluctuation of internal flow in vortex pump

为深入研究由叶轮与蜗壳间动静干涉引起的内部流场压力脉动特性,基于RNG k-ε湍流模型,运用ANSYS CFX软件对额定工况下的旋流泵进行先定常后非定常数值模拟,分析蜗壳无叶腔中间截面和后缩腔叶轮中间截面上共19个监测点的瞬时静压值、标准差、时域和频域变化规律。计算结果表明:各监测点的瞬时静压值均呈现周期性变化,蜗壳后缩腔与叶轮圆周间隙处监测点的脉动幅值最大,叶片流道域的监测点次之,蜗壳无叶腔的监测点最小;蜗壳静止域内的后缩腔与叶轮圆周间隙处监测点、隔舌附近监测点压力脉动主频在叶频126.7 Hz处,无叶腔中心监测点压力脉动主频在轴频15.8 Hz处,其他监测点在轴频和叶频处脉动幅值相当,均可认为是主频。叶轮旋转域内监测点的压力脉动主频均在轴频处。结论可为研究旋流泵或相关设备的压力脉动、泵噪声以及稳定运行提供参考。

In order to further study the pressure fluctuation characteristics of the internal flow field caused by the rotor-stator interaction between the impeller and the volute,a steady and unsteady numerical simulation of a vortex pump under rated conditions was carried out using ANSYS CFX software based on the RNGк-εturbulence model.The changes of instantaneous static pressure,standard deviation,time domain and frequency domain at 19 monitoring points on the middle section of the volute bladeless chamber and backward shrinkage chamber impeller were analyzed.The results show that the instantaneous static pressure of each monitoring point changes periodically,with the greatest fluctuation amplitude of the monitoring point at the circumferential clearance between the volute back shrinkage cavity and the impeller,followed by the monitoring point in the blade runner region.The monitoring point without the volute blade cavity has the smallest fluctuation amplitude.In the static domain of the volute,the main frequency of pressure fluctuation is at 126.7 Hz of the blade frequency at the monitoring point at the circumferential clearance of the impeller and the monitoring point near the tongue.The main frequency of pressure fluctuation at the central monitoring point without blade cavity is at 15.8 Hz of the shaft frequency,other monitoring points have the same fluctuation amplitude at the shaft frequency and blade frequency.In the impeller rotation domain,the main frequency of pressure fluctuation is at the axial frequency.The conclusion of this paper can provide a reference for the study of pressure fluctuation,pump noise,and stable operation of vortex pumps or related equipment.