Four giant hydraulic turbines of Yantan Hydropower Sta-tion located on the Hongshui River,Guangxi Provinceare now under construction by the Harbin Electric Machinery Works(HEMW)of China Harbin Power-Plant Equipment Co...Four giant hydraulic turbines of Yantan Hydropower Sta-tion located on the Hongshui River,Guangxi Provinceare now under construction by the Harbin Electric Machinery Works(HEMW)of China Harbin Power-Plant Equipment Corporation(GROUP).The turbine will become the largest in dimension forFrancis type turbine ever made in China.The external diameter ofthe runner is 8.6 m,which is supposed to be ranked No.3 among thelargest runners of this category in the world.Each turbine is展开更多
The pressure fluctuation caused by unsteady flow in runner is one of the main reasons of vibration for a large Francis hydraulic turbine. It directly affects the steady operation of the hydraulic turbine unit. The exi...The pressure fluctuation caused by unsteady flow in runner is one of the main reasons of vibration for a large Francis hydraulic turbine. It directly affects the steady operation of the hydraulic turbine unit. The existing research of the pressure fluctuation in hydraulic turbine mainly focuses on the unsteady flow in draft tube. Accurate distribution of pressure fluctuations inside a runner is not very clear. In this paper, the numerical method for predicting the pressure fluctuations in runner is investigated and the numerical simulation is performed for a large Francis hydraulic turbine. It is proved that the combination of shear-stress transport（SST） k-o） turbulence model and pressure-implicit with splitting of operators（PISO） algorithm could give more reliable prediction of pressure fluctuations in runner. The frequencies of pressure fluctuations in runner are affected by the flow in guide vane and the flow in draft tube The first dominant frequency is significantly determined by the flow in draft tube, especially at part load condition. This frequency is approximately equal to one-third of the runner rotating frequency. The evident second dominant frequency is exactly equal to the guide vane passing frequency. The peak-to-peak amplitudes of pressure fluctuations in runner at small guide vane open angle are larger than that at large open angle at the same operating head. The amplitudes at points on blade pressure surface are generally greater than that on suction surface. The research results could be used to direct the hydraulic design and operation stability improvement of a large Francis hydraulic turbine.展开更多
文摘Four giant hydraulic turbines of Yantan Hydropower Sta-tion located on the Hongshui River,Guangxi Provinceare now under construction by the Harbin Electric Machinery Works(HEMW)of China Harbin Power-Plant Equipment Corporation(GROUP).The turbine will become the largest in dimension forFrancis type turbine ever made in China.The external diameter ofthe runner is 8.6 m,which is supposed to be ranked No.3 among thelargest runners of this category in the world.Each turbine is
基金supported by National Natural Science Foundation of China(Grant Nos. 51079152, 91010003, 51079151)Research Fund for the Doctoral Program of Higher Education of China(Grant No.0100008110012)Beijing Municipal Research Fund of Commission of Education of China(Grant No. 20100909)
文摘The pressure fluctuation caused by unsteady flow in runner is one of the main reasons of vibration for a large Francis hydraulic turbine. It directly affects the steady operation of the hydraulic turbine unit. The existing research of the pressure fluctuation in hydraulic turbine mainly focuses on the unsteady flow in draft tube. Accurate distribution of pressure fluctuations inside a runner is not very clear. In this paper, the numerical method for predicting the pressure fluctuations in runner is investigated and the numerical simulation is performed for a large Francis hydraulic turbine. It is proved that the combination of shear-stress transport（SST） k-o） turbulence model and pressure-implicit with splitting of operators（PISO） algorithm could give more reliable prediction of pressure fluctuations in runner. The frequencies of pressure fluctuations in runner are affected by the flow in guide vane and the flow in draft tube The first dominant frequency is significantly determined by the flow in draft tube, especially at part load condition. This frequency is approximately equal to one-third of the runner rotating frequency. The evident second dominant frequency is exactly equal to the guide vane passing frequency. The peak-to-peak amplitudes of pressure fluctuations in runner at small guide vane open angle are larger than that at large open angle at the same operating head. The amplitudes at points on blade pressure surface are generally greater than that on suction surface. The research results could be used to direct the hydraulic design and operation stability improvement of a large Francis hydraulic turbine.
