Control of secondary flow loss in turbine cascade by streamwise vortex

An experimental and numerical study of flow control in a high-loaded turbine cascade was performed in order to reduce the secondary flow losses by means of streamwise vortices. The interaction mechanisms between the streamwise vortex and the secondary vortex and the impact of the streamwise vortex position on the performance of the turbine cascade are discussed in detail.The results indicate that streamwise vortex can effectively reduce the stagnation pressure loss and the flow deviation. The control effect is significantly dependent on the relative location of the streamwise vortex with respect to the cascade. It can suppress the development of the pressure side leg of the horseshoe vortex better if the streamwise vortex is close to the suction side of blade leading edge. The experimental and computational results in this configuration show a decrease in stagnation pressure loss at the cascade exit by 6.5 ± 1.0% and 5.4%, respectively.

► We study a secondary flow control method in high-loaded turbines by means of streamwise vortices.
► Streamwise vortex can effectively reduce the stagnation pressure loss and flow deviation.
► Control effect depends on the relative location of streamwise vortex with respect to blade.
► Control effect is the best when streamwise vortex is close to blade suction side in this research.