Blade aerodynamic force and tip region vortex spatial-temporal evolution study of a compressor cascade

Abstract

This paper utilized a numerical simulation method to get the vortex structure and aerodynamic force in a low-speed compressor cascade at 5-deg incidence with a hybrid unsteady Reynolds averaged Navier-Stokes/large eddy simulation (URANS/LES) turbulence model. The aerodynamic force, tip leakage vortex (TLV), and the mainstream flow interaction, especially in the blade tip region, are well analyzed. The instant flow pattern showed that the tip secondary leakage vortex and trailing edge backflow radial vortex occur by turning in the tip region. The spanwise flow pattern analysis exhibited that the dilation item dominates the tip region flow instability. The integral aerodynamic force at different spans showed that the tip region aerodynamic forces are far greater than that of mid-span and root-span. The correlation analysis between the aerodynamic force peak and the vortex structure showed that the float in and out of the trailing edge radial vortex closely relates to the aerodynamic force peak value change. The proper orthogonal decomposition (POD) mode results showed that the static pressure on the blade surface refers closely to the leakage vortex structures. The POD time coefficient curves and the aerodynamic force wave results showed that the tip secondary leakage vortex and the radial vortex at the trailing edge in the tip region dominate the aerodynamic force in the tip region. This research found a correlation between the POD mode time coefficient and blade aerodynamic force.