The Research Of Scale Effects About Vortex In Horizontal Hydraulic Intakes Of Pumped-Storage Power Station And Numerical Modelling

The vortex often appears in hydro-engineering, especially at the intakes of hydraulic structures. Sometimes the vortex develop to air-core vortex, which can damage the hydro-engineering or hydro-machine. Generally, the vortex at the intakes is an eddy with lesser dimension. To some extent, it is similar to cyclone or ocean circumfluence, especially in movement discipline, which gives it the important significance. Study on the movement discipline, inner structure and the reasons of start is the foundation of recognize the vortex and dismiss it. Model experiment is a normal method to learn the vortex disciplines at intakes of hydro-engineering. As a weakness, the model can't as same as the proto type for the scale effect. Base on the results of present investigation, by theoretic analysis and physical model experiment and numerical modelling, the research of scale effpcts about vortex in horizontal hydraulic intakes of pumped-storage power station is carried out. The main contents are as follows:(1) By analyzing the problems of vortex at intakes of hydro-engineering, the main results of eliminating vortex at intakes are summarized. For example: the courses of vortex ,the eliminating and use of vortex , the numerical modelling of vortex. The main contents are submerge depth of intakes, boundary conditions , scale effects and the effect of Coriolis force.(2) Combining the theory of hydraulics and eddy moving, Some basic eddy are studied. For example, the exact solutions of point unit vortex , Rankine vortex , Oseen vortex are studied, the characteristic of them are discussed. Through the effect of viscous force, the difference between several vortex above and vortex in practical engineering is showed, which can provides certain help to modeling vortex at intakes.(3) Taking the intakes of one pumped-storage power station as prototype, the experiments of some intakes are carried out, scale of the intakes is 1: 15, 1: 20, 1: 30, 1: 60, 1: 80, 1: 100. Through the charts and theoretic analysis, the rule of scale effects about vortex at horizontal hydraulic intakes of pumped-storage power station is researched. For vortex at horizontal hydraulic intakes of pumped-storage power station, the results indicate that the Re number is more than 3×10~4 and the We number is more than 120 which are based on the follow conditions: the models which the scale is from 1:15 to 1:20, the experiment can be simulated with the flow range from 1.0 to 1.5; the models which the scale is from 1:20 to 1:60, the experiment canbe simulated with the flow range from 2.0 to 2.5. And the scale effects can be neglected, the pattern of vortex in model can show the shape of vortex in prototype. Based on the model which the scale is 1:20, the numerical modelling of vortex at intakes is built. The apply of VOF model in multiphase flow is discussed. The difference between the results of physical model and the results of numerical modelling is analyzed. The results can be used for studying the numerical modelling of vortex at intakes ulteriorly.