Prediction of Runaway Characteristics of Kaplan Turbines Using CFD Analysis

In case of disconnection generator from the network and failure governor, rotational speed rotor rapidly increases achieves maximum value, called runaway speed. Prediction at stage runner design would allow to select a considering this characteristic. Given in paper is numerical prediction for Kaplan turbine. Two approaches simulation were discussed. first one, flow turbine passage was simulated using 3-D RANS equations incompressible fluid k-ε turbulence model. second approach, cavitation phenomena taken into account two-phase Zwart-Gerber-Belamri (ZGB) CFD calculations carried out with CADRUN solver. When setting boundary conditions, head, being difference energies inlet outlet cross-sections, pre-set as constant while discharge torque are determined process computation. The computed compared that obtained model tests. It shown better matching experimental data.