| In recent year, with the rapid development of hydro-engineering construction in China, the techniques about energy dissipation and erosion control downstream the discharge works are rapidly, which leads to a lot of new energy dissipaters be put forward.The development of new energy dissipater bases on the traditional energy dissipater, so it's very important to study the hydraulic characteristic of the traditional energy dissipater. There are four types of traditional energy dissipaters: energy dissipation by hydraulic jumps, ski-jump energy dissipation, rolling current energy dissipation and bucket energy dissipation. The bucket energy dissipater was widely used in the hydraulic and hydroelectric engineering for its simple shape, low quantity and excellent energy dissipation effect. The hydraulic characteristic of the bucket energy dissipater is analyzed and discussed through model test research.The characteristic of the traditional energy dissipater and the development of new energy dissipater technique and its usage are talked first in the thesis, and then the recent research state and the existing problems of bucket energy dissipater are discussed. At last, the research importance of the thesis: the research on the limit water depth of bucket energy dissipater is conformed.The hydraulic characteristic of roller bucket is studied in the thesis; the method to conform the shape of continuous roller bucket is introduced; the existed results about how to calculate the upper limit and lower limit water depth of roller bucket are discussed. Basing on this, the experiential formula is put forward, the joining condition of the roller bucket downstream stream and the method to calculate dissipation ratio are analyzed.In order to analyze the hydraulic characteristic more, the model test is studied. According to the condition and the text of the test, after comparing 5 types of calculation formula about the lower water depth, the practicability of the experimental calculation formula is showed. At the same time ,the upper limit of water depth, theposition and the depth of the washout, the surge height and the relevant dissipation ratio are studied and demonstrated.In the end, through the usage of the roller bucket in the Youfanggou hydropower station, it is explained that the text researched in the passage is directive to its usage in the actual engineering. |
