叶顶间隙对斜流泵叶轮内部空化流动的影响  

Effect of blade tip clearance on cavitating flow in mixed-flow pump

作　　者：黎义斌[1] 何慧 范兆京 李建忠 LI Yibin;HE Hui;FAN Zhaojing;LI Jianzhong(College of Energy and Power Engineering,Lanzhou University of Technology,Lanzhou,Gansu 730050,China)

机构地区：[1]兰州理工大学能源与动力工程学院,甘肃兰州730050

出　　处：《排灌机械工程学报》2020年第3期224-229,共6页Journal of Drainage and Irrigation Machinery Engineering

基　　金：国家自然科学基金资助项目(51866009)。

摘　　要：为了研究不同叶顶间隙值对斜流泵叶轮内部空泡稳定性的影响,获得叶顶间隙的最佳范围,基于标准SST k-ω湍流模型和均相流模型对斜流泵内部空化流动进行了数值模拟.结果表明:叶顶间隙对斜流泵叶轮内部空化性能有显著影响,小流量工况下随着叶顶间隙的增大,叶顶泄漏涡的湍流尺度和强度逐渐增加,临界空化数随着叶顶间隙的增大而逐渐减小;当临界空化数为0.357时,较大的叶顶间隙可以抑制叶片表面的初生空化;当叶片发生严重空化时(σ=0.123),较小的叶顶间隙抑制叶片表面产生大尺度空泡;当叶顶间隙较小时,空泡团稳定附着在吸力面;随着叶顶间隙的增大,空泡脱落区向主流移动并聚集在叶片吸力面中部,空化体积分数逐渐增大.Cavitating flows in a mixed-flow pump were numerically simulated using CFD software based on SIMPLEC algorithm and structured-mesh.The standard SST k-ωturbulence model and homogeneous flow cavitation model were adopted to investigate the influence of blade tip clearance on cavity stability in the impeller and obtain the optimum range of blade tip clearance.The results show that the blade tip clearance has a significant effect on the cavitation characteristics in the mixed-flow impeller.Specially,the turbulence scale and intensity of blade tip leakage vortex increase but the critical cavitation number decreases gradually with increasing blade tip clearance under part-load flow conditions.When the critical cavitation number is 0.357,a larger blade tip clearance can suppress the inception of cavitation on blade surfaces.When severe cavitation occurs at 0.123 cavitation number,a smaller blade tip clearance can inhibit large scale bubbles on blade surfaces.At a small tip gap,these bubbles are attached to blade suction side and become stable.With increase of blade tip clearance,the cavity shedding area is migrated to the primary flow zone and the bubbles are accumulated in the middle of blade suction side,and the vapor volume fraction and cavity thickness are increased gradually.

关 键 词：斜流泵 叶顶间隙 临界空化数 叶片载荷分布 空化 

分 类 号：S277.9[农业科学—农业水土工程] TH311[农业科学—农业工程]