Abstract: The sloped slotted compressor casing treatment is designed and researched with the help of an isolated rotor. The efficiency and stall margin have been effectively increased by the new kind of casing treatment. Various characteristics of this treatment have been evaluated. The general flow structure around the rotor has been shown. The three dimension flow field in the endwall region has been carried out through hot wire anemometer and phase locked average technology.The results show clear evidence of a leakage vortex core behind the rotor. The stall margin improvement is produced by both flow suction and injection from the treatment region. Because the broken line angle of slotted treatment casing may affect the injecting flow direction, it also affects the stall margin improvement.

Key words: slotted casing tr eatment, endwall flow, stall mar gin