Similarity of pressure fluctuation between prototype and model pumps
XU Zhe1, LIU Xueqin2, XU Xuemei2, LIANG Yunhui2, ZHENG Yuan1,ZHONG Ziye3, WAN Jinghong3, DAI Qifan3*
1. College of Water Conservancy and Hydropower, Hohai University, Nanjing, Jiangsu 210098, China; 2. Jiangsu Water Conservancy Survey and Design Institute Co., Ltd., Yangzhou, Jiangsu 225000, China; 3. Jiangsu Province General Irrigation Canal Management, Huai′an, Jiangsu 223200, China
Abstract：In order to study the similarity of the pressure pulsation between the prototype and model pump device, the similarity transformation hypothesis of pressure pulsation amplitude of the prototype and model was derived based on the similarity theory, and the hypothesis was verified by numerical simulation. Taking the Huai′an Fourth Station as the research object, the prototype and model axial-flow pump devices were numerically calculated using CFX, and the pressure fluctuation results of the pump section in time and frequency domains were investigated. Mass flow inlet boundary conditions and ope-ning outlet boundary conditions were used, and the SST k-ω turbulence model was adopted. The reliability of the numerical calculation method was verified by the model test of the pump working condition based on the high-precision hydraulic machinery test bench. The results show that the dominant frequency of pressure pulsation at impeller inlet is impeller blade passing frequency, while the main frequency of pressure pulsation at impeller outlet is the blade passing frequency of impeller or guide vanes. The dominant frequencies of pressure pulsation at the corresponding monitoring points of the prototype and model pump unit are consistent, and the corresponding amplitudes of the main frequency are also consistent. The simulation results have verified the similarity transformation hypothesis of pressure pulsation amplitude of the prototype and model devices to a certain extent. Especially, when the prototype and the model unit meet the mechanical similarity and the nD values are consistent, the corresponding pressure pulsation amplitudes are also consistent.
