In this paper a 3-D computational methodology for multistage turbomachinery flows is developed, validated, and applied in analyzing the reduced-massflow-rate operation of a 4-stage turbine. The flow is modelled by the 3-D Favre-Reynolds-averaged Navier-Stokes equations using the Launder-Sharma near-wall k- #epsilon# turbulence closure, which are integrated using an implicit 3-order upwind solver. The computation models the 8 blade-rows, including the tip-clearance gaps of the rotors, using a 6x10~6 points grid, and computes the time-averaged flow using mixing-planes between rows. Computational results are compared with measurements for various operating points. After this validation the method is used in a first attempt to analyze the 3-D flow at reduced-massflow operation.
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