Influences of trailing boundary layer velocity profiles on wake vortex formation in a high-subsonic-turbine cascade

Abstract

In this paper, delayed detached eddy simulations are performed to study wake flows of a turbine blade at a high subsonic exit Mach number, M 2,is ¼ 0:79, and high Reynolds number, Re ¼ 2:7 À 2:8 Â 10 6 , based on the chord length and outlet velocity. It is found that a slight change in the trailing suction profile would have a big influence on the formation of wake vortex street, which is believed to be caused by the change in the boundary layer state near the trailing edge, and suction boundary layer with a fuller velocity profile tends to destabilize the wake flow, promoting the generation of wake vortex and enhancing the unsteady effect. Local spatial-temporal stability analyses of the wake velocity profiles suggest that wake flows with asymmetric velocity profiles might have a stabilizing effect. It is suggested that the vortex formation and its strength can be controlled by making some slight modifications on the rear blade suction surface, and the mixing loss in the wake can be reduced due to a weaker unsteady effect.

Effects of trailing-edge modification of guide vanes on the wake vortices under different inflow conditions

“…Lee et al 9 demonstrated that the cross-sectional shape of a trailing edge has a significant effect on vortex shedding. Same conclusion can be found in the studies of Donaldson, 11 Do et al, 12 Peng et al, 13 and Wang et al 14 Do et al 12 studied the flow past a blunt-edged two-dimensional NACA 0015 section with various base cavity shapes and sizes at high Reynolds numbers. The numerical prediction showed that the presence of a base cavity at the trailing edge of NACA0015 does not change the inherent Strouhal number of the 2 D section examined.…”

“…Same conclusion can be found in the studies of Donaldson, 11 Do et al., 12 Peng et al., 13 and Wang et al. 14 Do et al. 12 studied the flow past a blunt-edged two-dimensional NACA 0015 section with various base cavity shapes and sizes at high Reynolds numbers.…”

“…Peng et al 13 proposed an intelligent optimization model for the vane's trailing edge profile to eliminate the resonance of the stay vane. Wang et al 14 studied the wake flow of a turbine blade corresponding to a high Reynolds number using delayed detached eddy simulations. Wang et al found that a slight change in the trailing suction profile had a significant influence on the formation of the wake vortex street.…”

“…Wang et al. 14 studied the wake flow of a turbine blade corresponding to a high Reynolds number using delayed detached eddy simulations. Wang et al.…”

Numerical Study on the Biomimetic Trailing Edge of a Turbine Blade Under a Wide Range of Outlet Mach Numbers

“…They find that the microtubes can reduce the blade profile loss by 3%. Wang et al (2019) study the effect of the degree of suction-side convexity on the vortex shedding. Through the local spatial-temporal stability analyses, they find that the wake velocity profiles in the near-wake region are more unstable for a fuller suction boundary layer.…”