Transient flow characteristics of water distribution ring pipe of impulse turbine under load rejection condition

A model of the water distribution loop, nozzle, and deflector for a certain impact power plant in China was established. Unsteady calculations were conducted using a water gas two-phase model.The dynamic grid method was used to study the dynamic changes in flow velocity and pressure generated by the six nozzle water distribution loop during the transition process.Research had found that during the closing process of the water distribution ring pipe, the pressure change of the bifurcated pipe only increases in the inlet section of the pipeline, and the pressure distribution at all points after the inlet section follows the same pattern.At the beginning of the action, there is a pressure decrease trend, followed by a convex shaped pressure change rule.When the opening is closed to 0.5, there will be continuous high-frequency fluctuations, and when the opening is around 0.375, the first peak of pressure rise will be reached.When the opening reaches around 0.19, the second peak will be reached.The calculation results of the three-dimensional transition process are consistent with the pressure distribution law of the one-dimensional calculation method. © 2024 Huazhong University of Science and Technology. All rights reserved.