The Study On The Influences Of The Bucket Lips' Selection To The Nappes And The Pressure On The Slabs

Based on the study about the influences on the hydraulic characteristics of the nappesexerted by the shape of the bucket lips, this thesis includes following three parts.First, founded on the existing research about the diffusive regularity of jet flow, theauthor analyzed the diffusion of nappes that flowed through surface outlets and broughtforward the main influencing factors. According to the results of existing research,continuous bucket lip is very useful in arch dam because it is economical and easy toconstruct, but the same time, it also caused some problems such as centralization of flow,huge impact pressure and so on. How to settle down these problems is one of the mostimportant works in the arch dam design and daily operation. Tongue bucket lips andasymmetry bucket lips had been adopted in arch dam construction so as to improve the flowpattern of the nappes. But there were no available method to calculate the nappes of these twokind of bucket so far. Seeking this method is the main purpose of this thesis. The CADmodels of the different bucket lips(continuous bucket lips,tongue bucket lips,asymmetrybucket lips) were constructed first for further calculating and researching. The diffusiveregularity of jet flow was put forward;whereafter basing on the regression analysis method,the formulas were established. According to the results of calculations, the pattern of the flowthrough the tongue bucket lips was improved in contrast to the water through the continuousone, the width and thickness of the nappe also increased obviously, and the air concentrationincreased simultaneously. Asymmetry bucket lips can alter the direction of the water flow.Second, with main researched results of free impinging jets, the diffusive characteristicsfor an oblique-submerged turbulent impinging jet in a plunge pool and variations of mainphysical variables in the different jet sub-regions are analyzed in detail. The disciplinarian ofimpact pressure on the plunge pool exerted with the jet flow was given. Utilizing thecaculated data, the distribution of pressure on the slab of plunge pool were made out.Third, the collision of water jets from surface outlets with those from middle outlets wasdiscussed. Though computing the hydraulic parameter of the collided jets flow, the authorbrought forward the influencing factors as well as the optimal flow ratio between surface andmiddle outlets.Then, in order to resolve the problems about water jet concentration, optimized projectwas given.