Simulation of pressure fluctuation and flow induced noise of pump turbine in load rejection of pumped storage unit
FENG Jun1, MAO Xiuli2*, ZHENG Yuan3, CHEN Diyi2, DONG Zhenghao2
1. Power China Zhongnan Engineering Co. Ltd., Changsha, Hunan 410014, China; 2. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China; 3. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, Jiangsu 210098, China
Abstract：In order to investigate the characteristics of pressure fluctuations and its influence on flow induced noise in the transient process of load rejection under pump turbine power generating mode. A domestic pumped storage power station unit was taken as the research object. Based on the mesh sliding technique and the separated vortex turbulence model of detached eddy simulation, three-dimensional calculating of transient period was carried out by ANSYS software. The pressure signals acquired from flow field was treated as a source for the further study the flow induced noise in sound field by using LMS software. The results show that the flow field in two vaneless regions was widely divergent, which due to the different influence form rotor-stator interaction(between stay vane and guide vane)and rotor-rotor interaction(between guide vane and runner). The change trend of pressure on both sides of guide vane was completely different. The main frequency of pressure fluctuation from runner passage was located at blade passing frequency(St=0.676 3). The sound pressure field noise distribution in pump turbine presents obvious dipole characteristics, which become extremely serious under small flow condition(smaller than 0.2QBEP), wherein the maximum sound pressure reaches at 130.00 dB and the minimum sound pressure value is 9.67 dB. The pulsations of sound pressure level were similar at diffe-rent moments in external sound field of pump turbine, the overall trend was that the intensity of sound pressure increases as the flow reduction. However, the change of flow rate has no effect on the distribution pattern of noise which indicates that the improvement of pressure fluctuation in pump turbine was a way to decrease the sound level of flow induced noise.
冯俊,毛秀丽*,郑源,陈帝伊,董正豪. 抽蓄机组甩负荷过程压力脉动及流动噪声仿真[J]. 排灌机械工程学报, 2021, 39(7): 678-684.
FENG Jun,MAO Xiuli*,ZHENG Yuan,CHEN Diyi,DONG Zhenghao. Simulation of pressure fluctuation and flow induced noise of pump turbine in load rejection of pumped storage unit. Journal of Drainage and Irrigation Machinery Engin, 2021, 39(7): 678-684.
