Stability analysis of axial compressors with wire mesh casing treatment

Abstract

Experimental results indicate that wire mesh casing treatment (WMCT) enhances the stability of low-speed compressors with little reduction in efficiency. The flow resistance on the surface of the grooves, which are formed by the wire mesh, provides a new variable for the design of WMCT. This paper investigates the stability improvement induced by three different meshes through experiments and steady numerical simulations. A stability prediction model incorporating the effect of WMCT is developed to assess the stability of the steady flow field, and the results show that the predicted stall points of the compressor are close to those of the experimental data. The stability analysis model has a well-defined theoretical foundation in which the meridional flow field of the compressor is considered as the basic flow and the blade is replaced with a body force. This formulation enables fast and accurate stability assessments of compressors incorporating WMCT during the design process. Finally, based on the influence of the different meshes on the steady flow field, the stability-enhancing mechanism of WMCT is analyzed in terms of flow field details and macroscopic physical quantities. WMCT improves the flow around the tip region, shifting the tip blade loading in the aft direction and reducing the tip leakage flow. Macroscopically, the installation of WMCT makes the flow structure in the tip region less sensitive to changes in the compressor operating conditions.