THREE-DIMENSIONAL UNSTEADY TURBULENT SIMULATION OF THREE GORGE HYDRAULIC TURBINE AND ANALYSIS OF PRESSURE FLUCTUATIONS

摘要

Three-dimensional unsteady turbulent flow was simulated through the whole passage of Three Gorge Francis hydraulic turbine, and the pressure fluctuations were predicted inside draft tube, in the front of runner, wicket gate, stay vane, and at spiral case inlet. The calculated pressure fluctuations were compared with the predicted results of model turbine experiment, which showed that the calculation could simulate the pressure fluctuation in draft tube well. And the helical vortex rope in draft tube was analyzed to get the principle of its production and spread. Then the calculated results of the whole passage were analyzed, which demonstrated that the unsteady vortex rope in draft tube, rotor-stator interaction between wicket gates and runner were two main factors bringing the pressure fluctuations in turbine, and the pressure fluctuations spread inside the whole passage.