翘曲端壁对大折转角压气机叶栅流动的影响

研究了翘曲端壁对大折转角压气机叶栅流动的影响.结果表明:翘曲最高点位于压力面时效果较好,翘曲高度为2%叶高时出口总压损失下降约5.8%;而翘曲最高点位于压力面与吸力面之间时效果则不理想;翘曲高度为5%叶高、翘曲最高点距压力面为0.25倍节距时出口总压损失增加约3.4%,此时端壁附近压力梯度呈先顺后逆变化,低能流体由压力面端区迁移至10%叶高处与吸力面附近低能流体汇合,增加了流道内二次流强度;当来流攻角不为零时,下端壁翘曲所构造的反向压差对于减小二次流强度、降低出口总压损失的效果仍比较明显,+3°攻角下出口总压损失减小约5.6%,-3°攻角下出口总压损失减小约3.5%,但同时其导致的负荷沿径向重新分配也将使得上端壁附近流动状况也发生改变.

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.