叶轮斜切对导叶式离心泵特性的影响

为改善试验离心泵扬程曲线驼峰,斜切叶轮16.4°,通过试验探索泵扬程、效率、轴功率的变化,同时利.用标准SST湍流模型对主要工况Q(Q为额定流量)、0.7Q进行非定常数值模拟,研究叶轮斜切对泵压力脉动和叶轮径向力的影响。试验结果表明,叶轮斜切后各工况扬程均有下降,驼峰区减小;效率有所提高,在0.6Q附近效率增大最多(约2.1%);轴功率曲线整体下移,其中大流量区间轴功率减小更多。数值模拟结果表明,叶轮斜切前后的压力脉动主频均为叶片通过频率,斜切叶轮降低了各工况主频和高频的幅值;1个叶轮.旋转周期内的径向力变化轨迹与导叶叶片数有关,且不论叶轮斜切与否,Q工况径向力大于0.7Q,叶轮斜切使两工况的叶轮径向力下降约41%。

Influence of the Oblique Trimmed Impeller on the Characteristics of Centrifugal Pump with V aned Diffuser

In order to improve the stability of the lift curve of test centrifugal pump,the oblique trimmed impeller with angle 16.4° was researched.And the lift,efficiency and shaft power curves of the pump were obtained by experiments.Meanwhile the impact of oblique trimmed impeller on the pressure fluctuation and radial force at conditions of Q(Q is the designed flow rate) and 0.7 Q were studied by the transient numerical simulation with standard SST turbulence model.The experimental results of the oblique trimmed impeller show that the lift decreases at all flow rate conditions,and the area of the instability of the lift curve narrows;The efficiency improves at some flow rate,which achieves the maximum(about 2.1%) around 0.6 Q;The shaft power curve moves down,while the shaft power reduces greatly at the larger flow rate range.The numerical simulation results show that no matter for the original impeller or the oblique trimmed impeller the dominant frequency of pressure fluctuation is approximate to the blade passing frequency.However,the amplitude of the dominant frequency and high frequency of the oblique trimmed impeller is lower at both flow rate;The trajectory of radial force in one rotation cycle is related to the number of the vaned diffuser,and the radial force at Q is larger than 0.7 Q for both impellers,while the radial force of the oblique trimmed impeller is about 41% smaller than the original impeller under both operating conditions.