期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2012
卷号：15
期号：6
出版社：IOP Publishing
摘要：For a bulb turbine, it has a low head and a big runner diameter, and the free surface influences the flow at the inlet and outlet of the turbine, which bring many problems such as vibration, cracks and cavitation to the turbine. Therefore, it is difficult to get the precise internal flow characteristics through a numerical simulation with conventional ideal flow conditions. In this paper, both numerical and experimental methods are adopted to investigate the flow characteristics at the inlet and outlet of the bulb turbine with considering free surface. Firstly, experimental and numerical studies in a low head pressure pipeline are conducted, and the corresponding boundary condition according with reality is obtained through the comparison between the mod el test result and the CFD simulation result. Then, through an analysis of the velocity and pressure fields at the inlet of the bulb turbine at different heads, the flo w characteristics and rules at the entrance of the bulb turbine have been revealed with considering free surface; Finally, the performance predictions for a bulb turbine have been conducted by using the obtained flow rules at the inlet as the boundary condition of a turbine，and the causes that lead to non-uniform forces on blades, cavitation and vibration have been illustrated in this paper, which also provide a theory basis for an accurate numerical simulation and optimization design of a bulb turbine
