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Abstract

Axial compressors have inherently unsteady flow fields because of relative motion between rotor and stator airfoils. This relative motion leads to viscous and inviscid (potential) interactions between blade rows. As the number of stages increases in a turbomachine, the buildup of convected wakes can lead to progressively more complex wake/wake and wake/airfoil interactions. Variations in the relative circumferential positions of stators or rotors can change these interactions, leading to different unsteady forcing functions on airfoils and different compressor efficiencies. The current study uses an unsteady, two-dimensional thin-layer Navier-Stokes zonal approach to investigate the unsteady aerodynamics of stator clocking in a low-speed þstage compressor. Relative motion between rotors and stators is made possible by the use of systems of patched and overlaid grids. Results include surface pressures instantaneous forces and efficiencies for a þstage compressor conuration.



Karen L. Gundy-Burlet
Wed Apr 9 15:39:35 PDT 1997