Energy Dissipation Influence On Arrangement Type Of Energy Dissipator Suspension Grid In Underflow Energy Dissipation Basin

The rivers of Xinjiang mountain stream have a mass of suspended sediment and the sediment particle thickness uneven,for combining sediment discharged downstream stilling pool of bottom spillway structure,it is unfavorable to adopt baffle pier and other auxiliary energy dissipation energy dissipation;for the surface holes spillway stilling basin which has the larger flow of single wide,when using trapezoidal piers and other auxiliary energy dissipators of energy dissipation effect are not ideal,laying the suspension girder in the stilling pool can better solve the problem,the rapid flow of water pass through the stilling poold and getting obstructing、impacting etc by the suspension gird side wall,severe turbulencing, cutting in the hydraulic jump and forming circumfluence around the suspension girder,consuming energy,getting a steady flown of water,improving the flow pattern, reducing the maximum depth role of the stilling pool. Laying the energy dissipator suspension grid in the stilling pool both can not affect the flushing function and play the role of auxiliary energy dissipater,due to suspension grid energy dissipator reducing maximum depth of the pool combined with remarkable effect of the steady flow,it has practical value.Based on the previous studying of suspension grid stilling pool in Wuyi reservoir spillway structure, choosing the methods of uniform orthogonal design UL9(34) and projection pursuit regression in this paper,in order to further study the arrangement type of energy dissipator suspension grid effects on energy dissipation in underflow energy dissipation,under the suspension grid layout parameters absolute value of the condition in the stilling pool,electing the flow Q,suspension gird high hs、suspended grid spacing bs and figure as the factors of energy dissipation,using UL9(34) design with PPR modeling and simulating, getting the impact factor ranking of the suspension grid layout parameters on energy dissipation effect,and determining the rectangle suspension grid for optimal suspension grid size;in the design discharge working condition,focuses on studying suspension grid layout parameters effecting on the maximum water depth in the bottom flow stilling pool,selecting rectangle suspension grid number ns,suspension gird high hs、and suspended grid spacing bs as the factors on influence of energy dissipation,using UL9(34) design with PPR modeling and simulating,through the achievement of PPR simulating,getting the impact factors ranking of the maximum water depth as: ns> bs> hs.In different single wide flow working condition, after adding rectangular suspension grid in the stilling pool,the maximum water depth in the stilling pool can reduce 4.97 cm of the maximum water depth,with a drop of 15.84%, under the rectangular suspension grid layout parameters relative value of the condition,choosing hs/B、bs/B、ns、Q/B as the factors of energy dissipation,by using 9 groups of uniform orthogonal test data and 1 group boundary condition test for a total of 10 test to conduct PPR modeling,and reserving 37 groups test data for inspection,getting the rectangular suspension grid layout relative value parameters for the maximum water depth relative value hm/B impact factors ranking in stilling pool as: Q/B>ns>bs/B>hs/B,through collation and analysis the 144 groups of PPR simulation data with drawing contour maps,under different single wide flow,by pieces of contour maps getting optimization of regional of relative value hs/B and bs/B respectively between 0.5~0.65 and 0.2~0.3,the suspension grid number optimization of regional between 16~20,the maximum water depth and energy dissipation rate in this optimization of regional value better,this can provide the reference for suspension grid layout parameters in the stilling pool.Using RNG k-ε model,using the method of VOF to track the free surface,applying numerical simulation method to research energy dissipator suspension grid,the numerical simulation results are in good agreement with the model test,the numerical simulation achievement can provide reliable theoretical basis and reference for suspension grid structure optimization design.