|
With the development of hydropower engineering in our country, a lot of hydropower projects with high dams and large reservoirs have been constructed. However, the flow velocity of the outlet structures with the high water head is often as high as 30m/s or more, easy to cause cavitation on the surface of discharge structure, especially for the place of the gate slot. Based on the former research, this paper used a standard k-εturbulence model to simulate and calculate the flow velocity field of two-dimensional gate slot and the pressure distribution, established a three-dimensional mathematical model for the deep hole gate with a small opening degree, calculated the velocity field and pressure distribution of the three-dimensional gate slot, and got the distribution rate of the pressure, velocity field, turbulence energy,turbulent energy dissipation rate and so on, with the tunnel’s top axis, bottom axis, side axis and the axis behind the gate. The major work in this paper can be composed of three parts as follows:This paper simulated previous measured results by RNG k-εturbulence model, and the calculated value was consistent with measured value, which showed that the mathematical model and calculation method are reliability and validity. Then, the formation of vortex in gate slot, velocity field, turbulent energy and its dissipation rate of different width to depth ratio were simulated. The pressure distribution features of gate slots, with different width to depth ratio, stagger ratio, fillet ratio and slope ratio, were calculated. The excellent gate slot shape parameter was obtained based on the research and analysis, and then reduced the cavitation of gate slot effectively.A mathematical model of the deep hole tunnel gate in small opening degree was established, three-dimensional flow field of tunnel pressure segment and open channel after gate was simulated by RNG k-εmodel. Complex free surface after gate has been processed with VOF method, velocity field and boundary pressure distribution of three-dimensional gate slot flow was simulated to get the distribution rate of the pressure, velocity field, turbulence energy, turbulent energy dissipation rate and so on, with the tunnel’s top axis, bottom axis, side axis and the axis behind the gate. The calculated results were found to be basically consistent with the measured after a series of analysis and companson.
|