Turbine Cascade Calculations Through a Fractional Step Navier-Stokes Algorithm

Abstract

An explicit, finite-difference, fractional-step Navier-Stokes method is presented for the prediction of two-dimensional turbomachinery cascade flows. The method also accounts for three-dimensional effects due to radius and streamtube thickness variations. The two-layer Baldwin-Lomax algebraic turbulent model is used to effect closure and its practical implementation is discussed in detail. Three different flow problems are examined and compared with experimental and numerical results obtained elsewhere. These cases deal with transonic flows in the last stage of a steam turbine rotor and a low solidity turbine cascade, as well as the subsonic flow around an isolated RAE2822 profile. The latter case was used for comparing two different transition criteria, implemented in the present code. C-type computational grids are used which are quasi-orthogonal in the near wall region.