Effect of blade grid density and twist angle on the performance of bulb turbine

The development of low head hydraulic resources will be more and more inclined to adopt units with large capacity and high specific speed, that is to say, the tubular turbine is required to have greater flow capacity and output, and the performance of the turbine depends largely on whether the design of the flow passage parts, especially the runner blades is reasonable, to demonstrate the hydraulic performance of the number of blades and the torsional angle in the process of runner transformation In this paper, the effects of cascade density and twist angle on the performance of bulb turbine are studied theoretically. The results show that if the number of blades is properly reduced to obtain a wide and smooth energy characteristic curve, the efficiency under some optimal conditions must be lost at the same time, Increasing the torsional angle of the blade can increase the flow capacity of the runner, but the too large torsional angle of blade will make the processing of runner blade difficult. For the reconstruction of Weituo hydropower station, it is proposed to reduce the torsional angle of the blade and increase the torsional angle of blade at the same time, from 4 blades to 2 blades, and the torsional angle of the blade is increased by 4 degrees from the original design scheme. The reconstruction scheme in this paper provides a reference for similar engineering research.