Numerical and experimental investigations of unsteady 3-D flow through two-stage cascades in steam turbine model

Unsteady 3-D flows through two-stage stator-rotor cascade channels in a low-pressure steam turbine model developed by Mitsubishi Heavy Industry(MHI) are numerically investigated and compared with the experiments. The fundamental equations solved in this study are based on the compressible Navier-Stokes equation and the SST turbulence model in general curvilinear coordinates. The high-order high-resolution finite-difference method based on the fourth-order compact MUSCL TVD(Compact MUSCL) scheme and the Roe's approximate Riemann solver are used for the space discretization of convection terms. A parallelized LU-SGS scheme based on the pipelining algorithm is also employed for the parallel-implicit time-integration. Total pressures, static pressures and yaw angles of flow velocity vectors at the outlet of first-stage rotor, second-stage stator, and second-stage rotor obtained from the computation are compared with the corresponding experiments. Finally the reliability of both numerical and experimental approaches is discussed.