FLOW ANALYSES IN A SINGLE-STAGE PROPULSION PUMP

Steady-state analyses of the incompressible flow past a single-stage s tator/rotor propulsion pump are presented and compared to experimental data. The purpose of the current study is to validate a numerical met hod for the design application of a typical propulsion pump and for th e acoustic analysis based on predicted flowfields. ii steady multiple- blade row approach is used to calculate the flowfields of the stator a nd the rotor. The numerical method is based on a fully conservative co ntrol-volume technique. The Reynolds-averaged Navier-Stokes equations are solved along with the standard two-equation k - epsilon turbulence model. Numerical results for both mean flow and acoustic properties c ompare well with measurements in the wake of each blade row. The rotor blade has a thick boundary layer in the last quarter of the chord and the flow separates near the trailing edge. These features invalidate many Euler-prediction results. Due to the dramatic reduction of the tu rbulent eddy viscosity in the thick boundary layer; the standard k - e psilon model cannot predict the correct local flow characteristics nea r the rotor trailing edge and in its near wake. Thus, a modification o f the turbulence length scale in the turbulence model is applied in th e thick boundary layer in response to the reduction of the turbulent e ddy viscosity.