Study On Hydraulic Characteristics Of The Vertical Pipe Inlet/Outlet Of Zhirui Pumped Storage Plant

With the economic development in our country and the reform of the energy component,the urgent task has been to solve the problem of peaking capacity in order to meet the consumers' s requirements.The pumped storage plant has ability to fill valley and modulate peak,frequency modulation,emergency reserve and black start,which satisfies the need of power system.The hydraulic characteristic of inlet/outlet has great effect to pumped storage plant as an important component.In this paper,the hydraulic characteristics of the vertical pipe inlet/outlet has been studied through numerical simulation.(1)The mathematical model of vertical pipe inlet/outlet was developed.The numerical simulatioin results and model test results were compared and analyzed to verify the rationality of numerical simulation method.(2)The design shape of Zhirui vertical pipe inlet/outlet was simulated during pumping mode and generating mode.In pumping mode(outflow),there was large area of reverse flow which height was in the range of 1.5m in the section of trash racks.The flow distribution was in the range of 10.38%~14.68%.In generating mode,the hydraulic characteristics of design shape was good.(3)The optimized shape replaced the bend of equal diameter with a bend of gradual contraction and a transition section based on the design shape.The results show that the bend of gradual contraction and transition section could improve flow pattern in curved pipe,reduce the height of reverse flow area and make flow distribution better.The hydraulic characteristics of optimized shape was better than design shape's.The height of reverse flow area was in the range of 0.9m,while the flow distribution was in the range of 10.71%~13.82%.The effect between two inlets/outlets was also studied in pumping mode,generating mode and combination mode.(4)The flow sepeartion in the section of trash racks and diffusers was studied.The effects of diffusion ratio and Reynolds number were studied respectively.The research results provide reference for the study on flow separation in vertical pipe inlet/outlet.