Numerical Simulation Of Fish Passing Facility In Dipanzi Hydropower Station

The water retaining structure in the river stops the exchange of substances and energies between upstream and downstream and damages the stability of original ecological system, so it is of great significance for the diversity of aquatic ecosystem and the continuous restoration of river habit to carry out relevant studies on fish pass facilities.In this paper, a case study of the proposed project of fish-pass facilities in Dipanzi Hydropower Station located on Qinghai Province is carried out, the preliminary design scheme is simulated using MIKE software and the deficiencies is duly analyzed. In addition, this paper optimizes the preliminary design scheme by taking such measures as changing the structure of the end of vertical slot fish way, reducing the pavement thickness of the end of the overfall gap in the nature-imitated channel and adjusting the water depth of entrance of fish way. Following conclusions are drawn through the analysis of water level line and the velocity results to different schemes:(1) The water flow regime in the fish pass structure in the preliminary design is overall stable, except for the end of vertical slot fish way and the end of the overfall gap in the nature-imitated channel where the stream flows quite faster and the hydraulic conditions deteriorate, which brings difficulties for fish to sail upstream.(2) After the analysis of computation results to scheme I, it is believed that the scope of recirculation zone gradually decreases, and the water body in the channel has more fierce turbulence and the rate of energy consumption of unit water body in the pool room increases, along with the increase of the advance angle of division plate, which goes against fish migration.(3) Scheme ?-? improve the flow condition in the part with structural change of the end of vertical slot fish way, but the scheme ? of removing the separating pier worsens the hydraulic parameters in the upstream of th e part with structural change. The Scheme ? of the surface slope, the vertical flow rate and the lateral flow rate of the end of vertical slot fish way and the distribution of kinetic energy and the rate of energy consumption of unit water body in the pool room meet the requirements of fish migration.(4) With the decrease of pavement thickness of the end of the overfall gap in the nature-imitated channel,the scope of areas with high flow rate in the pool room and the average value of flow speed in the overflow port gradually decrease.When the pavement thickness is 10cm,the flow condition in the fish pass channel is most favorable to fish migration;if the depth of water of the entrance of fish pass structure increases to 1.3m,the flow rate of the overfall gap in the nature-imitated channel and in the pool room can be effectively improved,which meets the requirement of target fish migration.