平衡孔直径对离心泵小流量工况空化特性影响

发布时间：2018-10-04 23:26

【摘要】：为研究小流量工况低比转速离心泵的空化特性,以一台降速后的IS80-50-315型离心泵为试验对象,专门设计了更换平衡孔直径的装置,当平衡孔直径等于4、6、8和11mm时分别对0.4Q_d、0.5Q_d、0.6Q_d和0.8Q_d这4个工况进行测试并分析。结果表明,叶轮平衡孔直径增大,泵扬程减小,效率下降。小流量工况下,随空化数的减小,不同平衡孔直径叶轮所受扭矩与泵扬程均出现不同步的陡降,且扭矩有明显的匍匐变化,这主要是由蜗壳和叶轮之间的动静干涉引起的;同一空化数下加大平衡孔直径,扬程系数增加,叶轮轴向力减小,离心泵的抗空化性能增强;同一平衡孔直径下流量越小,离心泵越不易发生空化,但随着离心泵内空化的产生和发展,泵腔内液体压力的下降速率先增大后减小,叶轮轴向力具有先趋于平坦后急剧增加的规律。从抑制空化和减小轴向力的角度,提出平衡孔直径在6~8mm较为合适。
[Abstract]:In order to study the cavitation characteristics of low specific speed centrifugal pump under small flow condition, a device for replacing the diameter of balance hole was designed with a IS80-50-315 centrifugal pump after speed reduction as the test object. When the diameter of the balanced hole is equal to 4? The results show that the diameter of the impeller balance hole increases, the pump head decreases and the efficiency decreases. Under the condition of small flow rate, with the decrease of cavitation number, the torque of impeller with different balanced hole diameters and pump head are all unsynchronized and steep drop, and the torque has obvious creeping change, which is mainly caused by the dynamic and static interference between the volute and impeller. Under the same cavitation number, the diameter of balance hole is increased, the lift coefficient increases, the axial force of impeller decreases, and the anti-cavitation performance of centrifugal pump is enhanced. However, with the development of cavitation in centrifugal pump, the decreasing rate of liquid pressure in the pump chamber first increases and then decreases, and the axial force of impeller tends to flatten first and then increases sharply. From the angle of restraining cavitation and reducing axial force, it is suggested that the diameter of balanced hole in 6~8mm is more suitable.
【作者单位】：兰州理工大学能源与动力工程学院;兰州理工大学温州泵阀工程研究院;
【基金】：国家自然科学基金资助项目(51269011)
【分类号】：TH311

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