Parallel-Implicit Computation of Three-dimensional Multistage Stator-Rotor Cascade Flows with Condensation

This paper presents the recent progress in our research group for developing a parallel computational code which can simulate three-dimensional multistage stator-rotor cascade flows in gas and steam turbines. This code can calculate not only those air flows, but also those flows of moist air and of wet steam. We named this code “Numerical Turbine”. The fundamental equations consist of conservation laws of the total density, the momentums, the total energy, the density of water vapor, the density of water liquid, and the number density of water droplets and they are coupled with 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 Roe's approximate Riemann solver is used for the space discretization of convection terms. A parallelized LU-SGS method based on the pipelining method is newly employed for the parallel-implicit time-integration. As numerical examples, 2-D and 3-D flows of wet steam through two-stage stator-rotor cascade channels in a steam turbine are computed.