Numerical Simulation of Wet-steam Flows Through Turbine Cascades in Multiple Stage

Abstract

Wet-steam flows through steam-turbine cascades in a multiple stage are numerically simulated. Fundamental equations contain conservation laws of water vapor, water liquid, the number density of nucleus, momentum equations, and the energy equation. The SST turbulence model is employed to predict the eddy viscosity. The classical condensation theory is used for modeling homegeneous and heterogeneous condensatins. These equations are solved by the fourth-order compact MUSCL TVD scheme and LU-SGS scheme. As numerical examples, wet-steam flows through a single cascade channel developed by Bakhtar is calculated and the calculated results are compared with the experiments, and wet-steam flows through turbin cascades in a multi stage developed by Mitsubishi Heavy Industries are calculated assuming steady and unsteady states. Finally, the effect of the wetness in the stages are numerically predicted.