叶顶间隙对轴流泵外特性及空化性能影响研究

兰州理工大学学报 ›› 2022, Vol. 48 ›› Issue (3): 56-64.

叶顶间隙对轴流泵外特性及空化性能影响研究

赵伟国^*1,2, 程超^1,2, 薛子阳^1,2

1.兰州理工大学能源与动力工程学院, 甘肃兰州 730050;
2.甘肃省流体机械及系统重点实验室, 甘肃兰州 730050

收稿日期:2021-03-12 出版日期:2022-06-28 发布日期:2022-10-09
通讯作者: 赵伟国(1979-),男,山东东营人,博士,教授.Email:zhaowg@zju.edu.cn
基金资助:
甘肃省自然科学基金(18JR3RA149),国家重点研发计划项目(2018YFB0606103)

Study on influence of tip clearance on external characteristics and cavitation performance of axial flow pump

ZHAO Wei-guo^1,2, CHENG Chao^1,2, XUE Zi-yang^1,2

1. College of Energy and Power Engineering, Lanzhou Univ. of Tech., Lanzhou 730050, China;
2. Key Laboratory of Fluid Machinery and System, Lanzhou 730050, China

Received:2021-03-12 Online:2022-06-28 Published:2022-10-09

摘要/Abstract

摘要： 为探究叶顶间隙对轴流泵外特性及空化性能的影响,基于修正的SST k-ω湍流模型和Z-G-B空化模型,对350ZQ-70型潜水轴流泵进行数值模拟,对比分析不同叶顶间隙下轴流泵的外特性曲线、叶轮流道内的压力脉动、空泡体积分数分布等.结果表明:随着间隙的增大,泵扬程和效率降低;小流量工况下流动失稳现象明显加强,扬程曲线会出现驼峰现象;进口边近轮毂侧比近轮缘侧更易发生空化;设计流量下,轮缘间隙空化首先出现在叶片中部,而不是叶片进口;叶片背面空化会影响相邻叶片工作面压力分布;存在临界间隙值,未达该值前,间隙增大主要降低叶轮的做功能力,对空化性能影响不大,超过该值后,空化稳定性降低,诱导压力脉动;对于实验泵,临界值在1.5~2 mm;随着间隙的增大,轮缘处空化程度不断增强,进口边空化程度反而有所减轻;根据轴流泵叶轮组装结构,从保护轮毂叶轮体的角度考虑,兼顾做功能力和运行稳定性,实验泵选择间隙为1.5 mm较为合适.

关键词: 轴流泵, 非定常模拟, 空化流动, 叶顶间隙

Abstract: In order to explore the effect of tip clearance on the external characteristics and cavitation performance of the axial flow pump, based on the modified SST k-ω turbulence model and Z-G-B cavitation model, the numerical simulation of the 350ZQ-70 submersible axial flow pump in different tip clearance was carried out to compare and analyze the external characteristic, the pressure pulsation and the distribution of cavitation volume fraction in the impeller passage. The results show that the pump head and efficiency decrease with the increase of the tip clearance, the flow instability phenomenon is obviously strengthened under the condition of small flow, and the hump phenomenon appears in the head curve. Cavitation of inlet edge is more likely to occur near the hub than near the shroud. At the design flow rate, cavitation of tip clearance first appears in the middle of the blade, not at the blade inlet. The cavitation at the back of the blade will affect the pressure distribution on the working face of adjacent blades. There is a critical value of clearance, before this value, the increase of the tip clearance mainly reduces work capacity of the impeller, and has little effect on cavitation performance; beyond this value, the stability of the leakage vortex decreases and the pressure pulsation increases. For the test pump, the critical value is between 1.5~2 mm; The degree of cavitation of inlet is reduced with the increase of clearance; According to the assembly structure of axial flow pump impeller, in the light of protecting the impeller body, considering the work capacity and operation stability, it is more appropriate to select a clearance of 1.5 mm for the test pump.

Key words: axial flow pump, unsteady numerical simulation, cavitation flow, tip clearance

中图分类号:

TH312

赵伟国, 程超, 薛子阳. 叶顶间隙对轴流泵外特性及空化性能影响研究[J]. 兰州理工大学学报, 2022, 48(3): 56-64.

ZHAO Wei-guo, CHENG Chao, XUE Zi-yang. Study on influence of tip clearance on external characteristics and cavitation performance of axial flow pump[J]. Journal of Lanzhou University of Technology, 2022, 48(3): 56-64.

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