Research On Hydraulic Characteristic Of A Siphon Drainage And Irrigation System

For the advantages of simple structure,rapid set-off,easy operation,protection against sand and ice,nearly maintenance-free,etc,siphon flow path has been applied to many projects as water intake,spillway,pumping station and dock.In recent years,the enlarged ships request high design level to docks along with development of the science and technology,so the siphoning pipe is getting widespread attentions as a newtype of drainage and irrigation of the dock.The research on the hydraulic modeling experiments has been made according to the siphoning hydraulic characteristic of the 10-ten-thousand-ton class repairing Dock and 5-ten-thousand-ton class building Dock of Shandong Weihai . Numerical simulation further verified the experiment results.The hydraulic modeling was designed according to the gravity similarity criterion,it was a normal model,the scale factor was 1/20.(1)Irrigation systemThe modeling experiments for the original proposal were made first,optimal proposal was raised according to the results,further experiments verified that the negative pressure agreed with the standard and the irrigation time was reasonable.It measured the time from evacuation to normal operation,the supreme negative pressure on the hump suction,and the on-way resistance coefficient.The efficency of the energy dissipation grille was analyzed , and the diagrams of discharge coefficient-time,water head-time,discharge-time were given.(2)Drainage systemThe results of the modeling experiments illustrated that the pressure on the hump suction agreed with the standard and the flow pattern is steady.When the primary pump started to run at the rated discharge 12400 m3 h,the pipes were not full at the hump,evacuation was requied.(3)In the numerical simulation,RNG k-εmodel was used to close the equation group,FVM to disperse the equation group,and PISO algorithm to solve the the equation group.The numerical simulation agreed with the experiment results.