Numerical Simulation And Experimental Study Of The Pressure Fluctuation In Water Turbines

Pressure fluctuation is a common problem in large-scale hydraulic turbine, which will affect the performance of the water turbines, such as negatively affecting the efficiency, increasing the damage of related components and decreasing the life span, bringing up great potential troubles to the operation safety of large-scale water turbines. The mechanism how the pressure fluctuation appears is due to the low-frequency pressure pulsation in the draft tube and the mid-frequency pressure pulsation generated by dynamic and static interferences before the runner transmit upstream, and the low-frequency and mid-frequency pressure pulsation in the front of the runner, guide vanes, fixed vanes and the inlet of the volute.To study the relationship between the capacity and the pressure fluctuation of the water turbine, the CFD calculation was performed on the water turbine and the results of the calculation were compared with the measurements in this study. The model of water turbine studied in this paper is Baihetan HEC_1014-type. The computations were carried out in the whole runner blade passage and the boundary conditions were set as the same as the experimental conditions. The unsteady state flow of the turbine was computed. The effects of turbulence were modeled with standard K-S turbulence model. The inner flow field and the pressure fluctuation were obtained from the calculation solver of Fluent. And the simulation are compared experimental results.