Effect of the leading-edge vortex generator on the performance of the linear cascade

Abstract

In this paper, based on the airflow improvement mechanism of dragonfly wing veins, a vortex generator is designed at the leading edge of the suction surface to improve the flow condition of compressor cascades. The influence of the placement positions and geometric dimensions of the vortex generators on the flow field structure and aerodynamic performance is investigated by numerical simulation. The research reveals that vortex generators at the leading edge of the suction surface can generate induced vortices near the end wall, suppressing the accumulation of low-energy fluid in the corner region. This results in a backward shift of the separation initiation point, a reduction in the corner separation region along the pitch direction, and a reduction in flow loss. The vortex generators exhibit favorable characteristics with positive incidence angles. However, when the incidence angle is below the minimum loss incidence angle, the vortex generators increase the flow losses of the cascade. Optimum performance is achieved when the vortex generators are positioned at the start of the corner separation. The flow control influence initially increases and then decreases as the height of the vortex generators increases. Similarly, the control impact is enhanced and then weakened as the placement position moves away from the suction surface. The flow losses decrease by 10.3% when the vortex generators are placed at the junction between the end wall recirculation and the mainstream region at a height equal to 2% of the blade height.