Investigations in recent years showed that three-dimensional blade design using end bend

sweep and dihedral could reduce endwall loss

improve efficiency and stable operating range.STR (straight)

SWF (forward swept)

SCB (incorporating forward swept and positive curved) and SWB (backward swept) rectangular compressor cascades have been studied at design and off-design incidences to verify if SCB can achieve better aerodynamic performance.All types of swept or curved blades considered are symmetric to midspan

consisting of an circular arc section in the central part and swept or curved sections toward the endwalls.The effect of incidence change on the distribution of exit total pressure loss and secondary flow vectors of the compressor cascades has been experimentally investigated.Ink-trace flow visualization on blade surfaces was also conducted in a part of incidences.Compared with straight cascade

mechanisms of the total pressure loss increase and decrease with the change of incidence of various swept cascades at different spanwise positions were analyzed.The results show that compared to swept-forward cascades

the swept-curved cascade further prevents the low energy fluid accumulation

which may induce separation in the endwall/suction surface corner region;therefore

remarkably reduce total pressure loss in that region.Even at larger positive incidence the total loss of the swept-curved cascade increases smoothly and no flow separation was observed in the corner.In general

the total pressure loss of swept-curved cascade is not sensitive to incidence change.The study supports the conclusion that SWF and SCB conduce to the improvement of stall margin near the endwall even at higher incidence.Moreover

it is supposed that better aerodynamic performance of SCB can be achieved by increasing design incidence at midspan and by optimizing the matching of swept blade angle and height

and curved blade angle and height.