Research On Hydraulic Characteristics Of Curvilinear Deflecting Bucket

With the construction of our national economy and the quick development of waterconservancy, lots of high-head and large-scale water and electricity projects are being builtand will be building. Most of these projects are more than 200-meters high, so the research onhydrodynamic design and energy dissipation of the discharged building has been crucialproblem.The article looks back the application and the development of the energy dissipation,andmakes a summary of various of deflecting buckets. Based on the research of the former work,systemic research on hydraulic characteristics of curvilinear deflecting bucket are carried outby the method of academic analysis and model tests. It includes structural design, flowpatterns, discharged capability, distribution of pressure and velocity, phenomenon ofcavitation, calculation of horizontal length of jet flow, scour area, the contrast of energydissipation rate and atomization effect. The principal content and achievement are concludedas followed:1. Based on experiment and dimensional analysis, the formula of the transversal diffusionwidth of the bucket is obtained. It includes the radius curvature, jet trajectory angle, the widthof the outlet section, the mean velocity on the flip bucket and the hydraulic head betweenupstream and downstream. Using such a formula, the nappe's width can be worked out.2. By model tests hydraulic characteristics of the curvilinear deflecting bucket arecompared with the general deflecting bucket's, diffused deflecting bucket's and diffusedcurvilinear deflecting bucket's. The discharge capability of curvilinear deflecting bucket isuniformed with the general deflecting bucket's, the flow patterns are favorable, thedistribution of pressure and velocity is well-proportioned and reasonable, and phenomenon ofcavitation hardly appears.3. The meanings and the sorts of fluctuating pressure are introduced. The fluctuatingpressure of side face and bottom of deflecting bucket is measured, so is the plunge pool's.Statistical eigenvalues and distributing map are given out. It is indicated that fluctuatingpressure of curvilinear deflecting bucket is more intense, effect of energy dissipation is morepreferable, and the sympathetic vibration will not happen. Fluctuating pressure of downriver plunge pool is less, and the change's range is also less.4.The formula of the horizontal length of jet flow is be educed, the results of the modeltest are well according with the results of calculation. The flow patterns of unrestricted watertongue and scour theory of bedrock is introduced. The model tests show that horizontal lengthof jet flow is much more far and the scour is much more flat compared with other shape'sdeflecting bucket's, so the curvilinear deflecting bucket is more appropriate to the large-scaleprojects.5.The theory, kinetic disciplinarian and harm of atomization is introduced. Theatomization of curvilinear deflecting bucket is more serious than general deflecting bucket,which is an disadvantage of curvilinear deflecting bucket and need to be improved.