Influence of bump end wall on cascade flow of high turning-bowed compressor

The influence of bump end wall on flow cascade of high turning-bowed compressor was investigated. The result shows that the influence is better when the bump salient point is located on the pressure side, and the outlet total pressure loss obtains 5.8% reduction when the height of bump is 2% of the whole blade height. However, a poor result may be obtained as the salient bump point was located between the pressure side and the suction side. When the salient bump point of the end wall profile is 25% pitch away from the pressure side and the height of bump is 5% of the whole blade height, the outlet total pressure loss may get an increase of 3.4%, and the pressure gradient near the end wall changes from positive to negative, thus making the low energy fluid near the end wall of the pressure side transfer to the position of 10% of the whole blade height on the suction side and join into the low energy fluid near the suction side, strengthening the local secondary flow. As the angle of attack changes, the reverse differential pressure constructed by the lower bump end wall can still obviously reduce the intensity of the local secondary flow as well as the outlet total pressure loss; the outlet total pressure loss obtains a 5.6% reduction at the angle of attack of +3° and a 3.5% at the angle of attack of -3°. Meanwhile, the redistribution of the load along the radial direction due to this differential pressure will also change the flow near the upper end wall.