MULTIPASSAGE 3-DIMENSIONAL NAVIER-STOKES SIMULATION OF TURBINE ROTOR-STATOR INTERACTION

This article deals with the development and validation of a three-dime nsional, multipassage, Navier-Stokes code for predicting the unsteady effects due to rotor-stator interaction in turbomachines. Prior work i n two dimensions has demonstrated the necessity of including multiple rotor and stator passages in order to closely approximate the stator-t o-rotor airfoil count ratio, and thus accurately predict the unsteady flowfield resulting from rotor-stator interaction. In this article, th is multipassage capability is extended to three dimensions. Numerical results obtained from a multipassage (three stator and four rotor pass ages) calculation of an axial turbine stage are presented. The stator- to-rotor airfoil count ratio (3:4) used in the present calculations is a close approximation to that in the actual turbine configuration (22 :28). The numerical results are compared with experimental data wherev er possible and to earlier single-passage calculations. The present mu ltipassage approach results in a more accurate computation of the unst eady flowfield than that possible from a single-passage approach.