Numerical And Experimental Study On The Hydraulic Characteristics Of The Throat-Type And Right-Angle Energy Dissipator

The application and the development of the flood discharge tunnel are reviewed in this dissertation, turbulence mathematical models are also summarized. The flow through the throat-type energy dissipator and the right-angle energy dissipator are calculated by using the two-equation turbulence model, which is expansively used to simulate the flow field successfully. The principal content and the achievement are concluded as follow:As a kind of internal energy dissipator in which the turbulent flow is contracted and expanded abruptly, throat-type energy dissipator was regarded as one of the potential energy dissipator for its many advantages, such as stable flow pattern, simple structure, easily controllable flow parameter, and anti-cavitation property. The numerical simulation was made on this kind of energy dissipator by using the k - s turbulence model, the full-field distribution of the time-averaged parameter and the turbulence parameter are described in detail, the calculated time-averaged pressure has good agreement with the experimental results, some advice can be provided for the further study and application in this thesis, especially the calculated results can be used to check the lowest time-averaged pressure.The experimental tests are made on the right-angle dissipator with square cross-section, a new internal energy dissipator. In order to obtain its hydrauliccharacteristic, LDA is used to measure the detailed velocity. The pressure along thewall boundary is also measured. The eddy was shown in the experimental results, and its height is about 20% of the tunnel height. Due to the existence of the eddy and the abrupt bend of the stream line, the pressure on the four faces has the distribution as follow: the lowest pressure appears at several centimeters after the angle point along the top boundary, the highest pressure appears near the center line of the vertical shaft on the bottom boundary, near the angle point, the pressure on the inner boundary decreases with the decreasing height, the pressure on the external boundary decreases slightly in the right-angle region, and increases obviously near the corner.The turbulent flow through the right-angle energy dissipator is simulated by using the transient k - e model, and compared with the experimental results. The calculated result indicates the flow characteristic in detail. The calculated wall pressure is in reasonable agreement with the experimental data.