Influence of blade wrap angle on performance in T-mode multistage hydraulic turbine
LI Yanpin1, ZHANG Lihong1*, ZHANG Zichao1, CHEN Dexin2
1. College of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou, Henan 450045, China; 2. Xinfei Era Energy Polytron Co. Ltd., Zhengzhou, Henan 450000, China
Abstract：In order to study the influence of blade wrap angle on the performance of hydraulic turbine, taking a two-stage turbine as the research object, the runner blade wrap angles were designed as 20°, 30°, 40° and 50°, respectively, and the Fluent software was used for numerical calculation. The results show that the blade wrap angle has a significant effect on the turbine hydraulic performance. With the increase of the wrap angle, the turbine head increases gradually, and the efficiency first increases and then decreases. Under the design condition, when the wrap angle is 30°, the efficiency reaches 80.24%. Due to the negative circulation of the primary runner, the import circulation of the secondary runner is lower than that of the primary runner, resulting in the lower efficiency of the secondary runner than that of the primary runner. Through the analysis of the pressure pulsation characteristics, it is shown that the pressure pulsation intensity in the runner is higher than that in other flow passage parts, and the pressure fluctuation in the secondary runner is the strongest. The appropriate value of the wrap angle can reduce the pressure fluctuation amplitude of each flow passage component. For the turbine with 30° wrap angle, the numerical simulation results are consistent with the test results, which verifies the accuracy of the numerical simulation results.
