EFFECT OF AXIAL SPACING ON THE ROTOR/STATOR INTERACTION IN AN AXIAL FLOW COMPRESSOR

摘要

The unsteady flow field in turbomachinery is mainly characterised by the blade row interaction effects due to relative motion between stator and rotor blades. These interactions are known to cause aerodynamic excitations that can induce blade vibrations, generate discrete tone-noise and degrade aerodynamic efficiency. In order to gain insight into the variation of flow physics with the change in axial spacing between blade rows, an attempt is made in this paper to analyse the stator/rotor interaction in a single transonic axial compressor. FLUENT code, which uses finite volume method for solving Navier-Stokes equations, is implemented with k-ε turbulence model and standard wall functions. A hybrid grid with fine grid at the walls is used. Results are presented for the analysis of a single stage axial compressor for axial gaps of 20%, 30%, 40% and 50% of chord length. It is found that the unsteadiness in the blade passages increases with a decrease in axial spacing.