Experimental Research On Characteristic Of Suspended Grid Plunge Pool Energy Dissipation

The tunnel is a familiar water release structure, when stream flows in the tunnel it will possiblely appear half pressure flow, which will produce a series of disadvantageous influences to tunnel structure, such as stressing state, discharge capacity and outlet energy dissipation. Therefore, it is important to establish water- stilling device in tunnel.A new form of energy dissipater named suspended grid plunge pool is posed through the hydraulic model experiment of diversion tunnel in Jilintai first-order hydropower station, which is located on the bank of Kashi river, Xinjiang. Based on the model experiment, energy dissipation characteristic of plunge pool(before putting suspended grid) and suspended grid plunge pool(after putting suspended grid) are contrastly analyzed through main distinguish basis which is damping ratio, auxiliary distinguish basises which are the biggest water depth of plunge pool and swell in downstream. The experiment result shows that damping ratio is raised, the biggest water depth of plunge pool and swell in downstream are also reduced after putting suspended grid in the same stream condition. Therefore, suspended grid plunge pool is better than general plunge pool. The best arrangement form of suspended grid is achieved through putting different arrangement form of suspended grid in the suspended grid plunge pool. At the same time, 9 groups data are conversely choosed according to uniform orthogonal array from 71 groups observed data of suspended grid plunge pool, the mold is set up by the method of PPR, the surplus 62 groups data are used to proceed examination, the empirical type optimum design of experiments are proceeded inversely, all of these confirm that a lot of model experimental results can be replaced by a few of test times under nonstrict uniform experimental condition. The result can provide the feasibility reference basis for same kind of model design of experiments in future.