Effects of the Leakage Flow Tangential Velocity on the Blade Passage Flow in Shrouded Axial Compressor Cascades

This paper is concerned with the influence of the leakage flow tangential velocity, set by the relative motion between rotating and stationary surfaces, on the blade passage flows in a shrouded axial compressor cascade. The leakage flow tangential velocity is systematically varied in the newly developed cascade facility with full shrouded cavity geometry. Results show that increasing the leakage flow tangential velocity is decreased the overall loss. Thus, for the design point, the overall loss reduces up to 14% compared to that of the off-design point. Although the leakage flow tangential velocity is increased over the design point, the overall loss does not change. Also, the increased leakage flow tangential velocity acts to spread the loss core, which originally concentrated in the hub suction side corner, in the pitch-wise direction and to move it radially downward towards the hub: the high loss region becomes more two-dimensional and the region’s radial extent is reduced. Consequently, the resultant mixing loss between the passage and leakage flows are reduced near the hub and then the overall is decreased.