MODELING OF SPANWISE MIXING IN COMPRESSOR THROUGH-FLOW COMPUTATIONS

Although three-dimensional Navier-Stokes computations are coming into use more and more, streamline curvature through-flow computations are still needed, especially for multistage compressors, and where codes w hich run in minutes rather than hours are preferred. These methods hav e been made more realistic by taking account of end-wall effects and s panwise mixing by four aerodynamic mechanisms: turbulent diffusion, tu rbulent convection by secondary flow, spanwise migration of aerofoil b oundary layer fluid and spanwise convection of fluid in blade wakes. T his paper describes the models adopted in the DRA streamline curvature method for axial compressor design and analysis. Previous papers are summarized briefly before describing the new part of the model-that ac counting for aerofoil boundary layers and wakes. Other changes to the previously published annulus wall boundary layer model have been made to enable it to cater for separations and end bends. The resulting cod e is evaluated against a range of experimental and computational resul ts.